Pontiac Bonneville General Maintenance and Repair

chasbville · July 2007

Hi, I had this problem on my 94 -- the car would shut off seemingly random, possibly going around curves, down hills, etc. After many expensive fixes, incl. new cam sensor, crank sensor, PCM, etc., none of which were 100% effective, somebody suggested that the panel in the throat of the air intake which swivels to reduce the air coming in may be getting stuck. I sprayed it with carb cleaner and that seemed to help. It's the $1.98 solution that just may work!

errk74 · September 2007

My 98 seems to be having that same problem. I was wondering if you found anything out. I changed the plugs, wires, and all 3 coils and its actually running worse. I cant figure it out and was hopeful that you could shed some light on the problem.

baseballjw · September 2007

I have a 1994 Pontiac Bonneville. My turn signal, both left and right, have stopped blinking. They'll turn on just fine though. Also, I guess I should note that the emergency flashers blink just fine. I'm pretty sure I just need to replace a fuse but I have misplaced my owners manual. If someone could look up or has a way to find out which fuse I need to replace that would be excellent.

P.S. 157000 miles very little maintenance and still goin strong!

asosocargirl · October 2007

I have a 98 bonneville, and turning to the left is easy, but turning to the right is hard beyond compare. I checked my power steering fluid and that is full. Has anyone had this problem?

ddebolt · October 2007

I'm trying to remove bolt from turbo idler, have been trying forever. Can not get it apart. Any ideas

jwally · November 2007

Problem#1 96 Bonneville SE, miles 249,626. I have a vacuum loud suction noise when pull dipstick out. I changed the PCV and installed old O-ring still did not help. any suggestions,thanks in advance. I also seem to be using a quart of oil for 1500 miles. I have also noticed a puddle of antifreeze on the intake manifold(metal)valley just below the Dormans plenum(about 2 years old)gasket. I try to tighten the bolt very slightly but still have it and I have been using a very little antifreeze.

Problem# 2 Also I get at times(idle or driving) a LOUD belt noise(squeeling). I do see the tensioner(only a few months old) pulley bouncing up and down at idle.I was told the tensioner must be defective. any suggestions,thanks in advance.

azu · November 2007

1) ?- Why are you checking oil level with engine running?
I had coolant collect there and it was from the hose on the thermostat housing.

2) My guess is that either your "new" tensioner is shot or one of the other pulley's bearing are shot.

jwally · November 2007

"Why are you checking oil level with engine running?"
The mechanic pulled it out and said I needed a PCV because there shouldn't be a vacuum at dipstick with engine running.I replaced PCV and did the same test he did and still get vacuum out of dipstick.
Thanks

wingnut8 · November 2007

1997 Bonneville 150,000 miles.
The electric door locks are not functioning, also the interior lights are not functioning, and there is a high pitched hum coming from under the dashboard while the car is off. However the noise changes to a beeping, clicking noise when the car is on and in motion.

azu · November 2007

I would start with cleaning the ground buss located next to the drivers seat next to the door. It is under the trim for the carpet. As far as hum it could be related but I'm not sure.

eidersanction · December 2007

I got a code telling me I had a No. 1 cylinder misfire. I replaced the plugs and wires. Once every couple of weeks I start the car and it runs like its missing. The next day I start it and it runs fine. The engine light hasnt come back on since I reset it a couple months ago when I changed the plugs and wires.

azu · December 2007

I would suspect a bad coil. Switch the position of that coil and see if you get a misfire on a different cylinder. If you do it is the coil.

Also make sure the wires are routed correctly and are not touching anything metal.

phillyfrank · January 2008

I have a 1997 Pontiac Bonneville SE with 115,000 miles and a 3800 engine. After long drives my check engine light comes on, it usually goes off after a few days. This week I drove over 150 miles straight and the light is on. It hasn't gone off in 3 days. Why does this happen? I was told I can't get my car inspected if the light is on. I have to get it inspected by Jan 31st. I don't have the money to get anything done besides the inspection. What can I check to get the light off? Thanks

jackv239 · January 2008

I have a 94 bonneville with a bad oil leak on the back top side of engine. Can anybody help me. I changed the rear valve gasket. but it still leaks. I need some help!

vcrespo · January 2008

hey phillyfrank. do you have a obd2 scanner? or do you know someone who may have one? the scanner may tell you what;s wrong. also try disconnect the battery for 15 min maybe it would help..hope you get you're car inspected... i had the same problem with my engine light one. i borrow a obd scanner from my friend and was able to fix my problem on my mitsubishi error p0405 egr.

vcrespo · January 2008

hey jackv239 have you check where the oil is coming from? also check the rear valve gasket and make sure the oil is not coming form there..also make sure all the bolt are tight.... hope this will help.

rstrunk · February 2008

I just bought a 1994 and I have this very same problem. The engine will "miss" slightly while accelerating but one i reach about 50 miles per hour and it shifts into overdrive it misses badly and shakes sometimes violently. If i put fuel injector cleaner in the gas it helps a little. I just got the car and haven't replaced anything. i was planning on starting with the plugs and wires and go from there. I read through this forum and have seen this problem brought up quite a lot but still have seen no advice on what to do to cure it. Any help is greatly appreciated.

clidog · May 2008

from the first day ,i bought this car used i went thru batteries and alternators like crazy.i just had two sensors installed and i do not think it helped. when i am driving and i try to stop the cars die on me .when i start up again the car is okay until it is time to stop again,can you give me a clue as to what is going on.

dmax_me_am · May 2008

My Bonneville catalytic converter is loose on the inside, what a noise, and needs replacing so I thought of replacing it with a high flow converter. However with all the stuff out there which one would improve mileage in town most that won't break the bank. In city driving is a scant 15/17 mpg but on the road 32/34 mpg I am hoping to improve the city mpg most. Anyone have any ideas? Brand, design, alternatives?

lastwraith · May 2008

It's pretty unlikely you are going to improve gas mileage with any kind of converter purchasing acrobatics. But at least with the new one you will be able to pass inspection with flying colors. If your cat is partially plugged, the new one may net you an increase in gas mileage since the car won't be choking as much on it's own exhaust. Other than that, you aren't going to see any gas mileage improvements....and certainly not selectively in the city portion.

dmax_me_am · May 2008

Thanks for your insight.

richard82 · May 2008

My 1998 Bonneville SLE with auto temp control seems to be having an A/C compressor clutch failure. I noticed a "metallic rattling" sound coming from the serpentine belt end of the engine. Inspection revealed metal "dust" around the front of the A/C clutch assembly and also just below it on the radiator hose. Since it seems that the clutch is self-destructing, my question is; Can the clutch assembly be serviced or replaced without taking the whole compressor out of the car and having to drain and recharge the R-134 coolant? Also, can the car be driven in this condition or will the failing clutch result in a much bigger problem if I do? Any help would be greatly appreciated. Thanks
Richard82

lastwraith · May 2008

Surely, enjoy your ride!

rider401 · June 2008

Hi all,

well, that stalling problem started last summer 2007, the codes checked nothing. It was a big problem and unsecure one too as its stalled at any place...It was good for some days, than stalled again.When it does, it is OK to turn on after 2-5 minutes, and you can go...you can be 2 days before it does it again.Its stopped doing this last winter(Montreal winter)...now summer is back and the stalling too. It was very hot 3 weeks ago but not humid...nothing happened then, since 3-4 days now its hot and humid and the problem emerge again...that is why I think humidity must be part of the deal here.If someone have any clue for me, I will be glad, as its not the best to stall wherever the Bonneville wants to....

Thanks for your time.

bonneville96 · August 2008

Hi, all,

Does anybody have a solution for my problem?
I have been trying to pass inspection for the past two weeks but without success. The first time the system said that my OBD is not ready, particulary Cat. Converter, Evaporation system, and O2 sensor.
My Check Engine light was on for a few weeks but it turned off a week before the inspection. Also, the day when the light turned off, I was driving from NJ to NY, and my engine died twice in 10 minutes :sick: , but restarted after a while, and did not give me any more troubles afterwards. It was giving me continuous warning chimes before dying, but nothing other than that. :confuse:
Now, my mechanic and another one at the dealership told me that after the Engine light goes off, the OBD computer needs some running time to reset itself, so I just have to drive it around for a while, and there is no other solution. The scanner did not give any error codes, just said that the OBD is not ready for inspection. I already drove it for over 100 miles, but the result is the same. I asked if disconnecting the battery would help, but my mechanic said it won't.
Did anybody have this problem?

dadscar2 · September 2008

I had a problem very similar to what yours sounds like with my 93 Bonneville this past spring. I ended up at the dealer since I was out of town at the time and it was shaking so badly, I did not think it would make it 200 miles home. And it was drinking gas like crazy! I had replaced the front wheel bearings myself a couple months earlier--had they somehow come loose? That might cause a rough ride, but not the gas drinking...

Turned out to be one of the engine coils had gone bad so I was running very roughly on 4 out of six. Cost me about 160$ at the dealer, but you can get new ones at O'reilleys for $45 or so. and they just pop out with a screw driver in about 10 minutes, you can replace one. After I got home, I replaced the other two myself just to be sure the others would not crap out while I was on the road somewhere. Hope this helps.

dsroth · September 2008

I am helping a neighbor with her 1988 Bonneville. The serpentine belt keeps falling off when we start the engine. We have replaced the belt which took a fair amount of movement of the tensioner to get the belt on. However, the belt immediately comes off when we crank the engine.. Help!

David

imidazol97 · September 2008

do you hear noise when the motor starts like the belt is being loaded by something not turning? Or does it just loosely run off.

One possibility is you're not putting it on right? Are you following the picture that's under the hood somewhere on many cars?

Or one of the pulleys is not turning freely is one possibility.
The idler pulley is one candidate that may have worn the bearing and be running the belt off angle.
You're going to have to rotate the various pulleys. Push and pull and twist on them to see if they're okay.

The AC could be locked up and when the clutch tries to engage after the motor starts (there's a delay) it is pulling hard on the belt and making it come off.

But the idler pulley would be my guess.

Take a look along the belt and pulley's lengthwise when it's on to see if they are all perfectly parallel.

larry1956 · September 2008

Water pump pulley may be siezed up or idler. If there is A/C the clutch pulley should turn freely with engine off. Make sure you are putting belt on right according to diagram. Diagram should be under hood somewhere. I why are you changing belt?
Larry

dsroth · September 2008

Thank you... Yes! The belt was installed in the correct manner..
The orginal belt fell off which is why the nieghbor asked me to look at it. I installed a new belt and it immediately fell off when the engine turned over (it was tight before we turned over the engine). I did not hear any noises.

I double checked the diagaram for the belt to make sure. I can turn all pulleys except the crankshaft (?) and water pump pulley. The others (Power Steering, Alternator and A/C) all turn freely. I did notice some radiator fluid under the car but not sure how long it had been there.

How would I know if it is the Idler pulley versus the water pump? Note: That pump must be internal?

imidazol97 · September 2008

I already said those things.

imidazol97 · September 2008

Is the idler pulley arm under spring tension? You should have to rotate it toward the firewall with a socket wrench to get it moved to shorten the belt path to get the belt around it. Then you release it slowly against the belt.

It's sounding like you're saying the belt is not under tension at all. I'll bet the spring inside the idler housing has broken and there's no tension.

Drive belt tensioner:

rockauto.com

This is different than ones I've seen on 93, 98, 03 models. But there is a spring under tension in the unit somewhere.

dsroth · September 2008

Sorry,

I missed that reply... How do I know if it is the idler pulley or the water pump? Should the water pump pulley turn freely when the belt is not on? Thank you for your help!

dsroth · September 2008

The belt is installed correctly, under full tension and aligned properly. How do I tell if it is the water pump pulley or tensioner pulley?

kartwriter · September 2008

I am about to buy a 2000 Bonneville SSEi with the 3.8L supercharged V-6.
Can anyone give me a detailed factory recommended maintenance schedule?
The car presently has 128K on the odometer.

Thanks!

willriley · October 2008

My wife and I received this car from her grandfather... It ran just fine for us the first few months of us having it. I got a check engine light and it was a 41 camshaft sensor malfunction.
Very shortly after that the vibration dampner/crankshaft pulley started making a lot of noise so I changed it out with an after market replacement. While I was in there I changed out the magnet inside the timing cover.
I also changed out the crankshaft sensor but it won't start.
This is the weird part. I put the old pulley back in the establish if the replacement may have been defective and I got a weak spark of it, where as i got nothing with the new replacement part.
What in the blue blazes is happening with this thing!?!?
Is the gaping on the crankshaft sensor really that critical?
My kingdom for some advice...

danadino3 · November 2008

hi, pontiac bonneville started acting weird this moring. all of a sudden it just gives this jump, especially when between 20-40mph. the service engine light came on too. makes a weird sound when making turns. I hope it's not a transmission problem. thanks

gmerkt · January 2009

I went through this same goat-roping myself. It is like the owner's manual says, but the headlamp doesn't slide out easily. You have to kinda horse it around, manipulate it to the point you think you're gonna break something but it will come out. As I recall, with the screws out, you slant the inner end out and kinda work it toward the center of the car. It's a miserable fit.

I think when I was trying to figure it out, the answer came from this board.

phillyfrank · January 2009

I have a 1997 Bonneville with 115,300 miles and I have to put Dex cool in my radiator every week. There's no leak that I can see but the radiator's very low after a week.
Also, my turnsignals don't work and I put a fuse, but the hazards work. I have to get my car inspected and I was wondering if I can repair this myself? (I'm out of work and low on money) Can anyone help me? I'd appreciate it. Thanks, Frank

imidazol97 · January 2009

Do you hear the turn signal flasher click when you turn in on or off?

I believe it's up under the left side of the dash to the left of the steering column. It might be on the fuse block that's off to the left. The turn signal is different than the 4-way flasher.

I can hear mine clicking on the 98 and can't tell where it is up under there.

larry1956 · January 2009

Hi Frank,

If you read through the numerous post on the subject of intake manifold problems with this car, you'll soon learn that this most likely is your problem with the disappearing antifreeze. Antifreeze is leaking through the intake manifold gasket into a cylinder and blown out the tailpipe. Make sure your engine oil show no signs of antifreeze/water in it, if it does, don't run car again untill fixed or you'll damage the engine extensively. As for the turn signal, did you replace the flasher. There may be a separate flasher for turn signals vs hazards. Could be the switch in the column also.

imidazol97 · January 2009

>1997 Bonneville with 115,300 miles and I have to put Dex cool in my radiator every week. There's no leak that I can see but the radiator's very low after a week

Before panicking about the antifreeze let's ask some questions. Have you owned the car since new? If so has the upper intake manifold been replaced? How many miles ago?

If you bought the car used, how many miles on it and how many years. Take off the beauty cover on the motor by twisting the oil cap extension. Look at the intake manifold and look for three circles about the size of 50cent pieces. There will be a year on one of them when the upper manifold was made. If it's 1996 or 97, then you have the original intake. If it's later, the intake has been replaced once. If there are no circles, you have a replacement manifold that's not GM/Delco or whoever made them for GM.

Next, how does the DexCool look in the reservoir tank? Is it goopy and dark? Have you changed it every two years? It's supposed to last 5 years but reality is it should be changed every two years just like any other antifreeze--it's cheap.

Next take a close look around the upper intake where it mates to the metal lower intake with a good flashlight. Look for a brown trail if it has DexCool in it. You might have a leak where it meets the throttle body or at the bottom in that area. Sometimes the seals around the two openings that let coolant go to the throttle body to warm it start seeping.

The second route of failure is the EGR passage that goes up through the UIM. You see the outside tube that goes the lower intake. The gases then turn and go up through a metal tube above the lower intake manifold. The metal tube is the same size as the passage into the plastic upper. The heat deteriorates the plastic in the area of the two coolant passages for the throttle body and the coolant starts seeping out slowly. The plastic turns into little cube-like granules due to the heat.
Replacement manifolds _may_ have had a smaller tube that keeps the plastic cooler. If replaced early under warranty the Lower may have been replaced and had a smaller tube in it. Replacement uppers came with smaller tubes to insert into the old lower metal.

The replacement takes a full day for a medium mechanic. There are instruction pages. The replacement uppers are $125 approx. and couple of choices exist.

But first you must check the water pump for seep inside the pulley. Use a mirror. If you see powder that's red around that area you may have a drip that's being slung around and drying. Check the two 90 degree black plastic connectors that come out of the lower and go to the metal idle bracket if I recall correctly and the other is also in the heat hose circuit.

Check hoses and radiator for seeps.

If you still think you have a intake problem, check your plugs. White deposits indicate you're burning coolant in a couple of cylinders. Do you have an occasional miss upon starting or when the motor is running very hot (and the coolant is under full pressure)?

If the coolant has been ignored through the years, the lower gaskets may need to be done below the metal lower manifold to the heads and the block. That's an additional expense and time.

If the water pump has never been replaced, I'd really check there.

phillyfrank · January 2009

I bought the car in 05 with 95,798.miles on it. As you suggested, I took the beauty cover off and looked at the manifold, which has (2 half dollar circles and 2 small) I noticed some thick liquid at the bottom of the upper manifold, which looks and smells like the dex cool.
My radiator and reserve have thick brown goop, which I had flushed 3 years ago, but it's returned to the radiator (rather thick).
I had a new water pump put in 2 years ago but I'll check it as you suggested.

As for my turn signals, they gradually stopped working. They'd work slowly or sluggishly. Now they don't work and I no longer hear any clicking. My hazrd lights do work and seem to be the same bulb.
Thank You for your time and helping find one of the problems.

imidazol97 · January 2009

Dry up the current liquid around the manifold and heads by soaking up with paper towels. See how soon it reappears.

What was the date on one of the circles for the upper intake? If it was original to the car, it may have had a partial fix applied. I believe during 1999 is when GM changed the size of the metal EGR pipe.

DexCool develops a gooop if regular antifreeze (old style) is added to it. If the original wasn't changed and there was air in the radiator instead of it being full, the DexCool breaks down and can become corrosive as well as gooey.

You need to have the system flushed to remove the goop. But if you might be having intake work done, you should wait now.

What you're really looking for is a seep somewhere other than the intake manifold to explain the coolant loss. That's better than replacing the upper and the lower gasket.

For the turn signals, if both left and right kept going at the same speed, I'd vote for the flasher itself having died out. Since you say it slowly got slower that makes it more likely for my first check.

phillyfrank · January 2009

I dried the liquid and I'm waiting to see if it reappears. The manifold doesn't have a date on it. I'll be taking my car to get fixed and inspected, and I hope it doesn't cost much. I'll let you know what happens. Thank You for all of your help.

imidazol97 · January 2009

It doesn't have a date on it like this?

this one is from 1999, notice the arrow pointing to one of the four years.

charko2 · January 2009

Air bag chims when driving. Have a 03 bonnie se sedan only owner it has been dealer serviced. The air bag light comes on when driving and chims. It has not been in an accident, but might have taken a speed bump to fast.
Any one have similar problems. The waranty expired. :confuse:

scscars · January 2009

I had the same problem last year with my 2002 Bonneville. The culprit is likely to be an open circuit in the airbag control module. Since we had many large and deep potholes during the winter of '08, one of them was probably the culprit when the car hit it.

A new connector was required costing about $37. However, the real cost with this repair was the labor, since the dashboard has to be removed and the airbag system disassembled and reassembled. My dealer did the repair. Total cost: $375, also not under warranty.

charko2 · January 2009

Thanks, Since the car handles fine,I might decide to leave it alone until I get up to NYC in April. I am in Florida for the winter. I will be bringing it in to my Florida dealer for an oil change before I go up and see if he picks up the problem. If not,I will leave it until I get back to NYC and take it to people i can trust. :surprise:

phillyfrank · January 2009

The date arrow points to 00 on top of the manifold. Below is a photo of the leak, at the bottom of the manifold, under the nut. I also thing there's another leak.
In the 2nd pic there's something on the hoses at the bottom of the engine which looks like dex-cool. I'm bringing it to get inspected any day. I unhooked the battery to see if I could get the engine light off, but It didn't go off.

<img src="http://img.auctiva.com/imgdata/3/4/0/6/2/2/webimg/222589798_o.jpg

<img src="http://img.auctiva.com/imgdata/3/4/0/6/2/2/webimg/222590178_o.jpg

Pontiac Bonneville General Maintenance and Repair

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