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I replaced the radiator, thermostat/gasket and lower hose yesterday. After driving awhile the gauge would fluctate, then start to climb. Then if I turned a hard corner it would drop then rise again. The thermostat I purchased from Advance was the one for my Forester, but it looked different from the one I took out.
I wonder can I run the car without a thermostat.
Your comment about change on a hard corner sounds like there may be a air gap or steam bubble forming somewhere, and it shifts around. The temp sensor responds rapidly to being submersed, then in hot air. Best case - you haven't completely bled the system of air. Worst case is that you damaged a HG and keep forming a new bubble that moves around when you corner.
With OBD-II, I doubt that you could get away with running without a thermostat for too long. The temp sender is one of the things monitored for optimization, and the system would be fighting to control emissions with a cold engine. Eventually, you might cook the cat.
How do I get rid of the air bubble?
The car reaches operating temperature after three minutes, then starts to climb in temperature 11 minutes later. I wonder if my attempt to patch the old radiator from the inside (using foil tape in the upper radiator section) left some pieces in the system that is causing flow issues.
Certainly sounds like an air blockage somewhere.
Not sure that it is going to be too helpful in a modern flat four, but the trick used to involve removing top and bottom radiator hoses and thermostat, wedging the garden hose in at the hot return side and back-flushing to try and remove any gunk wedged in the engine. The foil tape does not sound a good idea.
On some engines there is a coolant bleed valve to remove air set high on the engine, often on the hot water feed or return to the interior heater. The interior heater is usually the highest point in the coolant loop so that it the probable concentration point for any air . If there is no bleed valve, you can try disconnecting the hose there and seeing whether you can force air out.
It's a tedious job and you may be better served taking it to a radiator shop and getting them to flush and refill.
Cheers
Graham
If I can get the nose of the car at a steep enough angle and let it run. The air bubble should work it way to the top of the radiator and maybe in to the overflow tank. Or shut the engine down and let the coolant flow back to the lowest point throughout the engine leaving the air in the radiator where I can fill after a couple of hours.
I checked the cooling system section of the shop manual, but don't see any mention of an air bleeder. Wes & Graham gave good advise on flushing and filling. If this doesn't help, then you need professional assistance.
Right now the car is in my driveway on ramps to drain the radiator. The engine is at 207'F, the radiator inlet is 107'F and the bottom is 60'F. I am pulling the new thermostat out and putting the old one in. But I am going to try and see if the water pump is moving.
Though, I should have heard some belt squeal if it was not turning.
I took of the bottom hose and thermostat, hand cranked the camshaft sprocket and saw that the blades in the water pump turned.
Next I will see if I can flush water through the radiator with the bottom hose off.
I can actuate the new thermostat with my fingers. Can't with the old one, but then the problem was a leaky radiator. I will put the new thermostat back in. Or put everything back together without it and see if it overheats to eliminate the thermostat.
The following is from the shop manual:
Trouble Corrective action
Over-heating
a. Insufficient engine coolant - Replenish engine coolant, inspect for leakage, and
repair.
b. Loose timing belt - Repair or replace timing belt tensioner.
c. Oil on drive belt - Replace.
d. Malfunction of thermostat - Replace.
e. Malfunction of water pump - Replace.
f. Clogged engine coolant passage - Clean.
g. Improper ignition timing - Inspect and repair ignition control system.
On-Board Diagnostics II System
h. Clogged or leaking radiator - Clean or repair, or replace.
i. Improper engine oil in engine coolant - Replace engine coolant.
j. Air/fuel mixture ratio too lean - Inspect and repair fuel injection system.
On-Board Diagnostics II System
k. Excessive back pressure in exhaust system - Clean or replace.
l. Insufficient clearance between piston and cylinder - Adjust or replace.
m. Slipping clutch - Repair or replace.
n. Dragging brake - Adjust.
o. Improper transmission oil - Replace.
p. Defective thermostat - Replace.
q. Malfunction of electric fan - Inspect radiator fan relay, engine coolant temperature
sensor or radiator motor and replace there.
Anyhow, I set a bunch of them up (hanging - don't let them touch the walls of the pot) with a thermometer on a slow heat, and charted their response to rising temperature. Pretty sick, eh??
The thermostat is at the bottom of the engine. Is the flow also reversed - in at the top of the radiator, and out the bottom? If so, then the tape you used at the neck is probably no further into the system. If not, you might have ingested it into the engine?
Now I am going to put it all together without the thermostat and see how it flows.
What does that mean for the engine? Details please.
Regulated temperature cooling water is one of the factors that determines cylinder combustion chamber temps, and this directly relates to burn efficiency and emissions. With a thermostat, the coolant will remain right around 200'F. Without it, I suspect it will stabilize around 130-140'F. Somewhere I once read that this 60-70' external change will result in a 100-200'F chamber internal change. Think of how your car runs when it is still warming up, and now it never gets there!
If the coolant remains below a certain threshold (and this varies engine to engine / year to year), the ECM will never switch from 'open loop' to 'closed loop' emissions control. That means it will continue to use a look-up table/map for determining fuel mixture, and not use the oxygen sensor feedback to regulate activity. Or, if it does go closed loop, the reduced burn efficiency will force fuel trim to the extreme end of the spectrum. None of this is probably good for long term operation. At minimum, you will start to throw codes, you could end up with misfires or a damaged catalytic converter.
Or, I could be full of BS, and this engine can handle it just fine and you will live happily ever after? Inquiring minds want to know!!
I have had to buy another car for my wife, but the Forester is worthless as is. If anyone has had any similar problem, or ideas on what might be done to resolve this, I would appreciate the info.
The '09/'10 Foresters do not have the bleeders; rather, the cap is mounted atop a raised area on the radiator and serves the same purpose.
Service recommended three cycles of the cooling fans with top-offs in between. Also, they said to put a funnel assemble on the radiator.
Well I am going to get that air out everyway I know how (incline plain, squeeze hose, folk dance, etc.)
Thanks everyone
When the weather is below about 45 degrees outside, my Legacy won't idle smoothly or reliably. Instead, it surges between 0 RPM and about 1,300 RPM, up and down, until it stalls. The colder it is outside, the worse the problem.
When I take my foot off the accelerator while driving, if the outside temp is in the 20s or 30s (or lower), idle drops to nothing and the engine stalls.
Both of these related behaviors happen while the engine is warm and while the engine is cold, though at startup wihen the engine is cold, it actually will run smoothly for about 20 to 30 seconds before the surging begins.
I replaced all vacuum lines, cannister, mass airflow sensor, throttle position sensor, purge solenoid control valve. No change, except that I no longer get a diagnostic code indicating that the purge solenoid control valve is stuck open.
Since that is apparently NOT the problem, I'm hoping someone will recognize it. It is definitely tied to outside air temperature. On those rare wonderufl winter days here when it's 50 or 60 degrees out, the car runs perfectly smoothly, as it should, no idle issues at all. Soon as the outside temps drop, the surging at idle issue begins.
A search of the forums here turned up two possibilities:
1. Leaky intake manifold gasket. I'll check for that.
2. K&N filter -- which I'm using. Next time I'm in town, I'll pick up a paper filter and see if that solves the problem.
Any other suggestions?
--ken
Try looking for things like the brake booster that use manifold vacuum but are not as likely to get warm fast, or at all. Pull those lines one at a time and cap the fitting with your finger.
Long ago I saw a guy use an unlit Bernzomatic torch with the gas on just a crack as a neat leak detector. He waved it over everything and waited for a response in RPM. >POTENTIALLY VERY DANGEROUS<... yet effective.... I cannot believe I even repeated this. DO NOT TRY THIS AT HOME.... PROFESSIONAL USE ONLY.
Prayed that inclining the car and topping off the radiator after each run cycle would solve the overheating.
Drove to work and back (76 miles). Stayed within two tick marks of center on the gauge.
Is there a rebuild kit for the alternator?
Congrats, also, on the cooling system - I hope it is a positive sign for future trips!
Is anyone else having this issue? I want to determine whether it is a problem that can be fixed or is just a 'works-as-designed' function.
Thank you.
It was the Idle Air Bypass Valve.
I unbolted it, disconnected the air lines, but not the coolant lines, sprayed out the lines and the innards with carb cleaner, then reconnected it. Works like a charm now.
There WAS quite a bit of gunk in one of the air inlets.
If the problem returns, I'll pick up one of these valve assemblies at the junkyard and replace mine.
Best,
kwc
I am thinking about removing the lower seal on the radiator cap. This is a new cap from Pep Boys. It is stamped with 16 lbs.
Also change the radiator cap same time as it is cheap.
Subaru also suggests to use OEM coolant as other coolant may not treat as well to Subie's internal aluminum parts as the OEM coolant.
When the coolant expands, it pushes out against the 16 lbs (yes, I recently realized that Subi systems run at 1.1 - 1.2 ATM pressure). Older caps were 1.0 ATM, or 14.7 lbs. That probably buys you another 10'F upper end on boiling. Anyhow, it is easy once fluid pushes past the lower seal to run out the barb and down the hose into the overflow. It really stays below the top seal without any pressure - gravity does the job. But if the upper seal isn't 100%, when the radiator pressure goes negative, air is pulled in past the upper seal or hose nipple, and no fluid is sucked back against gravity out of the bottle.
Look for the simple first. If everything is perfect here, it could still be a failed engine gasket that is providing the one way leak of air back into the system.
Make sense?
Also, can someone tell me the symptoms of a auto trans that has been towed over 20 mph, or has been towed on 2 wheels with 4WD engaged?
I would appreciate any advice!
Not sure if this helps or hinders your decision, though.
Cheers!
Paul
I went cheap on the thermostat though ($11 from Advance, $35 from Subaru). I am now changing my replacement philosphy. Since I am saving money on doing the repairs myself, I can purchase the parts from Subaru. That would eliminate some of the problems I have had.
I still plan on having Subaru do the Coolant Service, after I replace three more hoses(bypass, supply & return heater).
It was full (yesterday it was empty), When I took off the radiator cap, I heard a rush of air and bubbles gurgled up in the overflow tank.
The radiator cap is from Pep Boys, I am going to Subaru and get another one. It seems like the seal is a little deformed now.
The constant fill and suck out tends to have a cleaning effect on the radiator, depositing a thick layer of sludge in the bottom of the overflow tank. If you used it, that is where a lot of the Subaru Coolant Conditioning (ie stop leak) ends up, along with other garbage. If this level rises above the level of the bottom of the hose, it will clog the end. Coolant will flow into the tank, but no get siphoned back out.
Now, if you have AWD or 4wd.....you need a bearing press and a good bit of experience with such tool. Otherwise, you could have an assembly suddenly breaking in the press and flying who knows where. Best left to someone who has done these before. Here again, if you repack around 150-170K, you can avoid having to press in new bearings! Same interval applies to the hubs!
Be careful not to drive too long with little grease in them. Because if you over heat the knuckles, the bearing opening will distort and the new bearing will fail early. trick to avoid that is to service early again.
Two choices basically. Drive till it fails, 240K or more and replace everything including possibly the knuckle. Or service around 150K-170K and just have new seals, some cleaner and new grease. Currently using the Valvoline full synthetic in road tests. About $8 for a small can.
My 1999 2.5 Subaru has never had any problems except for the known separator plate leak. My mechanic fixed the plate with the new metal one. When he fixed the plate problem, he took the engine out and then put it back in the car. The leaks are gone, but I have a new issue.
It happens (usually) once a day and the problem happens at different times and road conditions. After I come to a complete stop, I can try to accelerate and the car starts moving with heavy hesitation. Its almost like someone is grabbing the front wheels. If you apply more pressure to the gas pedal, the car will continue to accelerate at a slow pace. Eventually when the car gets to 2nd or 3rd gear, the car accelerates at an expected pace. There are no noises or smells. When this problem happens, it is like the car is operating on a 40 to 50% acceleration reduction.
The mechanic did change my transmission fluid and he is a trusted mechanic. But the problem will not replicate on demand and the car is not giving any error codes.
Help - any ideas?
Jason Nance