Headgasket or Rings?

[bri26064]

First off I have had this problem for the past 2 or 3 years. My car keeps overheating, even on the highway. I have replaced the thermostat (couple of times), replaced the radiator and have flushed the system. The water pump has only 8,000 miles on it. I am not leaking any anti-freeze on the outer part of the engine, and my coolant level never goes down. I maybe have to put some in every 3 or 4 months.

So I am thinking that maybe it is a leaking head gasket. So I check the compression.
1 - 180
2 - 185
3 - 180
4 - 125
5 - 175
6 - 150

Now it looks like the rings. I put oil in #4 and #6 and both jump to 190. Now if it was the head gasket it shouldn't jump like that, right? I have only a couple of hundred dollars to do this. I am currently unemployed and I need this car for at least another year. I really need some helpfull opinions. Thanks for your help.

 

[wood_e]

Well, a funny thing about that... SHOs rarley **** HGs. I dunno what ot tell you. Is the engine actually overheating or does your gauge tell you it is?

 

[SHOtimer]

Well, the problem seems to be isolated to your rear bank. I would doubt that all three of the rear bank cylinders would have bad rings. So, IMHO you are looking at a head problem. These heads don't have a lot of tolerance to be machined, so I would look into a used replacement head and a new gasket.

Have you checked for hydrocarbons in the coolant, or coolant in the oil? I would verify one of those two before diving in deep.

Doug

 

[DHMag]

Well, the problem seems to be isolated to your rear bank. I would doubt that all three of the rear bank cylinders would have bad rings. So, IMHO you are looking at a head problem. These heads don't have a lot of tolerance to be machined, so I would look into a used replacement head and a new gasket.

Have you checked for hydrocarbons in the coolant, or coolant in the oil? I would verify one of those two before diving in deep.

Doug

good advice Doug, but dont you mean the front bank ?

he states the coolant level never goes down and that he tops it off every 3 or 4 months. a leak that small wouldnt cause overheating. also, a leak that small might not leak when the engine is running, only when the engine is shutoff. i have a leak like this.

head gasket problems and worn rings in a SHO motor are rare, but they can happen given unknown previous maintainance. i agree that the problem might be in the head, warped or whatnot. i want to also say it might be rings, but it doesnt justify the overheating.

is there ever white smoke noticed from the exhaust ? check your tail pipes for white/green color. if so, the cooling passage in the head gasket is leaking into the cylinder(s).

another test you can try is remove the radiator cap and start the car and let it idle until warm. youre looking for bubbles in the radiator. same can be done when running a compression test but heat doesnt play its role then.

 

[bri26064]

I have checked the radiator shops around here, but none of them have the hydrocarbon test. I asked the local checker and autozone and the clerks looked at me as if I was stoned. I would like to know for sure before I get into this.

 

[SHOtimer]

Haha, yes the front bank. Your local mechanic should be able to test your coolant for hydrocarbons. I don't have a tester, nor ever bought one.

Doug

 

[artsho]

Do your fans come on

 

[bri26064]

Fan works great, and comes on like it's supposed to.

 

[matt59]

By the shear Compression numbers I'd go with rings, however you might have a valve problem. Do a leak down test to be sure. That will tell for sure if it is rings or valves.
I just tested a used motor and found it had a valve problem.
Not sure about the overheating. Are there bubbles in the radiator or the overflow bottle? I also recomend testing your coolant for hydrocarbons. At least you can rule out one of the suspects.

 

[LOUDSHO92]

Have you pulled codes? Could it be the temperature sensing unit?

 

[Red Devil]

Coolant pressure test. If you can't get to an autozone to borrow it, go buy one at sears. This will let you determine if it was a cracked head, blown head gasket etc. if it isn't too small. If it's that small then the hydrocarbon test is it.

As mentioned, a leakdown will help you pinpoint where a problem may exist. You may be able to determine if it's valves by pressurizing the cylinder and opening the valve cover to listen for escaping air.

 

[wood_e]

Do a leakdown compression test

 

[revhardSHO]

What exactly is a "leakdown" test anyway?

 

[Red Devil]

Here's a decent intro...

http://vmaxoutlaw.com/tech/leakdown_tester.htm

...along with instructions on how to build one. I'm lazy and bought one.

 

[RStalveyARFF]

I know snap-on makes a hydrocarbon tester because I've borrowed it from my coworker.