Engine Problems (1997 GTS)

[SilverViperGTS]

A compression test has revealed that my engine has bad compression in cylinder no. 8 ( only 90 psi). However, all other cylinders got around 160. My mechanic told me that some oil was present on the new spark plug.

Is it necessary to perform a leak down test? What do you think could cause this problem?? To my knowledge, my engine doesn't have any problems of oil consumption. I went to the garage because of a check engine code (missfire). They changed the spark plugs and the wires and then they performed the compression test that revealed bad compression.

I also noticed that the engine was running hotter just before the check engine light appeared.

Thanks for your help. I hope it is not a major issue.

 

[Schulmann]

Hi JG,

Yes, the best thing is to perform a leak down test. It will tell exactly what is going on, how bad the situation is. The compression is just used to compare the cylinders. What was your compression on the other cylinders ?

It can be a faulty valve, etc.

Ask them to have a combustion chamber cleaning. However combustion chamber cleaning might also worsen the trouble.
There are also sealers available etc. There is plenty of solution before you are forced to rebuild the engin. And I tell you this from personnal experiences ... Unless the leak down test reveals something really bad your viper can still run a couple months.


Finally, if you are looking to rebuild the engin, have a look at Track Racing in St-Eustache. They seems to have a HIGHLY qualified engin builder there.


The cause ? Poor quality oil, missed oil change. What I can tell you that I change my oil and the plugs every 1000mi-2000mi since my trouble. For frequent racing use 15w-50. And avoid the Mopar oil ...

 

[AviP]

Is it necessary to perform a leak down test?

Miles? Mods? If you don't have many miles, fresh gaskets and another compression test would be the first approach. If you have lots of miles then a leak down test will give you a more complete answer.

 

[SilverViperGTS]

Around 30k miles. No mods except for smooth tubes, K&N filters, cats and muffler delete.

I use 100% synthetic Motul oil only.

 

[Russ M]

You are the original owner?

I dont see how the motor could have gotten hurt the way it did with your mods.

Has it ever run low on oil? Smoke? Burn oil? Had other mods that are not there anymore?

The more you tell us the better.

 

[SilverViperGTS]

</font><blockquote><font class="small">En réponse à:</font><hr />
You are the original owner?

I dont see how the motor could have gotten hurt the way it did with your mods.

Has it ever run low on oil? Smoke? Burn oil? Had other mods that are not there anymore?

The more you tell us the better.

[/QUOTE]

No oil consumption issue at all. I am not the original owner though. I only see smoke the first time I start the car after winter.

 

[Russ M]

Did you have the motor checked before you bought it? How many miles were on the car when you bought it?

Sounds like someone sold you their problem, does it look like the car may have had more mods on it? Specificaly nitrous?

Any chance the car still has warranty, if not try to buy an extended one before you go to the dealer. Perhaps one of the big viper parts dealers can sell you an extended one, and then you can get your motor fixed under warranty. Otherwise you are looking at a good chunk of change.

 

[SilverViperGTS]

Compression was checked when I bought the car.

Anyway, how much do you think it can cost me?

 

[Russ M]

Depends on what you actualy want to fix, or improve on.

Just to fix the problem maybe 4-5k, to make the motor better and have more power while you are already at it maybe 10k.

You can always do a very simple job by just replacing the 1 damaged ring/piston if the cylinder wall is not damaged. But I would not recomend doing something like that on a nice car. It will probably cost several thousand to go this route.