advice needed on head gasket

leomort

I have a '94 Toyota Paseo w/ 160K on it. Last May I had tune up and compression test down and found one of the cylinders was low. This May while having the drive belts, timing belt and water pump changed, the mechanic noticed the head gasket had a minor leak. I got a quote from the Toyota dealership of $1000+tax to fix.
I'd like to keep the car at least until the Fall 2002, preferable to Fall 2003. I'll have 200K by Fall 2002 or 225K by Fall 2003. I don't if the head gasket can last another 40-65k.
From the advice I'd gather so far, the consensus seem to be that I can another 20-25K max. out of the car before needing to replace it.
By Nov of this year, I'll have another 15K on it. The mechanic said the head gasket would give the most trouble during the winter, so it looks like it could need done as early as this winter.
Would replacing the head gasket allow me to get another 50-60k out of the car? Or is this the tip of the "ice berg" on more major repairs to come? Kind of weird putting a $1000 into a car worth $500. But if that save you from a new car for 4 years???
I'll keep an eye on the coolant level, especially during winter, but what are some of the warning signs that the head gasket is going and needs replaced?
Thanks for the advice and help.

Leo

Mr_Shiftright

Your explanation is a bit confusing. Your low cylinder is probably not related to the head gasket, because it would have to be low in two adjacent cylinders for it to be a head gasket problem OR you'd have to have a compression leak to a water jacket in one cylinder. So you probably have other problems causing low compression.

If they are talking about an EXTERNAL leak in the head gasket and coolant dribbling out, then you have two problems...low compression (bad valve or camshaft) and a deteriorating head gasket.

I'd say you need to have a cylinder leakdown test done and first figure out what's really going on with this car. The diagnosis you were given is not satisfactory. Why does this car have low compression?

Now, if what they are saying is that they want to do a head gasket AND a valve job on your car, I personally don't recommend this on such a high mileage engine unless you are willing to possibly have to spend more than $1,000. It COULD work out okay, don't get me wrong, but it could also create oil burning and added stress on an old engine.

leomort

Last May when I had a tune-up at the Toyota dealership, the mechanic also did a compression test and only said pressure was low on one of the cylinders. Never got an explaination as to why, only that this is common on older cars with high mileage and it isn't anything to be too concerned with.
This May when I had the drive belts, timing belt, and water pump changed at the Toyota dealership, the mechanic pointed out a minor coolant leak from the head gasket. When I informed him about the compression test done last May, he told me that's the reason for the head gasket leak. To get it fix the gave me a price quote: $225 for head gasket, + $750 labor (13 hrs est.) and 85 misc in case something else is need + tax.
Sounds like its a lot more serious. Any advice how to approach this mess/headache.

Leo

isellhondas

Is probably being caused by carbon build up.

Try running a can of carbon remover through the intake system. It's amazing how that will restore compression.

Then add a can of Rislone concentrate to the oil. I can't believe it but this stuff REALLY does work...it's amazing.

The head gasket? Probably something to keep an eye on only, they can seep for a long time. If it fails completely, you'll know it!

Mr_Shiftright

You might do what Isell suggests, and then have the head torqued down and then add a small amount of stopleak. Worth a try.

No, I don't think this diagnosis you are getting is entirely correct. I fear you may replace the head gasket and still have low compression.

leomort

I talked to the people at Toyota dealership. The two main reasons for low compression in the cylinder are 1) Rings and 2) valves. He suspects that it more than likely the valve(s). But I'm not burning any oil so it doesn't look like real bad valves.
Where would I add the can of carbon remover? The intake systems? Is that the same as adding the can of Rislone to the oil?
The coolant leak was external and looked minor. It was on the side where the belts and water pump which explains why it wasn't found earlier.
Thank you both for your replies. I really appreciate it.

Leo

isellhondas

Is the term the shops use. You'll have to find a way to suck the stuff into the intake system, possible through a vacuum line. Rislone concentrate in the oil will help soften up the carbon. Two seperate items.

Once you have done this...this is important...take the car out and drive the hell out of it! If it's a stick, keep it near redline in third gear. Automatic ? use your lower gears.

You won't hurt a thing.

I've seen old time mechanics use plain tap water down the carburator to remove carbon. This REALLY works but it's risky if you don't know what you are doing.

I suspect the rings are fine.

isellhondas

When I bought my '72 MGA it wasn't running very well. Had leakdowns of something like 28 40 18 and 35. Gave it a double carbon blast and Rislone. Drove the bejeesus out of it and did a recheck. All cylinders were between 6 and 10 percent. What a difference!

leomort

Took your advice. bought an engine cleaner that suppose to clean the valves etc. and an engine restorer which is suppose to restore the compression. Both are suppose to last 3,000 miles. So I'll repeat it a couple of time w/ each oil change.

This is like the question which came first the chicken or the egg. Did the low compression cause the head gasket leak or did the head gasket leak cause the low compression?

So far no coolant leak but suspect the mechanic is right in that it won't be noticeable until winter time.

Leo

Mr_Shiftright

I don't think the low compression and the head gasket are directly related problems.

Isell---you are describing what is called "An Italian Tune-up", and there is more than a grain of truth to it for engines that like to rev but don't get what they need from their owners (drivers too timid). I guess I've never had the problem of carbon buildup because I drive the hell out of my cars. I take great care of them, too, of course!

You can have good valves and bad rings, and vice-versa. You can also have bad oil rings and good compression rings. There's all kinds of conditions an engine can settle into, and this is why diagnosis must be precise.

When a head gasket is torqued down, its function is to seal the compression in that one cylinder. When the gasket fails, the compression would only drop if the compression is leaking somewhere. Obviously, a huge compression leak in a cylinder has dramatic consequences, either water in the oil (gasket allows water galley to mix with oil galley), oil in the water (less common, depends on where head gasket fails), exhaust gases in the water (quick overheats) or compression exiting to the outside of the block (drastic noises).

Since you don't have any of those symptoms (unless the dealer missed them), what I think you have is low compression due to a bad or sticking or gummed up or badly adjusted valve, and co-incidentally a head gasket that has only failed to seal a water galley, but did not fail to seal compression.

leomort

Wow! You said the same thing the guy I talk to at Toyota: that the low compression is more than likely due to one of the valves sticking from being gummed up. That's why I bought a bottle of that Pennzoil Gunmount Engine cleaner that you add to the gas.

I never had my Toyota Paseo above 4,000 rpm. It redlines between 7,000-8,000 rpm. I guess I don't drive the car that hard.

The Toyota dealership suggested that whenever I have the head gasket done, also get a valve job done as well an extra $200-300 estimate. That would bring the total bill to around $1300+ tax. Is it worth get a valve job done at the same time? Can this be done cheaper?

Leo

Mr_Shiftright

I think the valve job should be based on a quantitative test, like a cylinder leakdown test. If the leakdown is very bad on the rings, I'd hesitate to do a valve job, because then you'll probably have an oil burner. But if the rings test out fine, but the valves show leakage, then you might want to do the valve job. If the valves are sealing well, then just do the head gasket.

leomort

don't know if it's related to the low compression/valves or head gasket but the car has started to show hesitation/bogg down. When in first or second, I notice that when I hit the gas but tried to up the revs the car is slow or hesitant to get there. I've had it happen twice on a slight upgrade and once or twice on flat service. On one of the upgrade the car jerk forward a few times. Is this related to the poor compression/valves? I hope it isn't my transmission (I drive a stick). Wondering if the engine cleaner I put in is clogging something? OR the engine restore additive I put in the oil crankcase?

Leo

Leo

leomort

Thank you for all your help. I appreciate it. We'll see how it goes. Thanks again.

Leo