Good or bad compression? 98 Yukon, 5.7 Vortec

[OilBurner2003]

Hey guys, yup, it’s me again. I eventually had problems again and took it to a shop. I’ve been so busy I haven’t had time to work on it.

They said the highest cylinder was 185 and the lowest was 150. I wasn't told which cylinders, but that number caught my eye. Btw, it’s in for rough idle. What do you guys think of this number?

Thanks! It’s a miracle I haven’t just bought a new vortec at this point.

 

[Hoesgottaeat2]

I've always been taught they should be within 15% of each other. Some say a little less or a little more. 150 doesn't sound devastating. Bu low compared to 185. Does it burn a considerable amount of oil as your user name suggests?
That low cylinder I'd suspect could be cause for your rough idle.
Are they proposing anything to remedy the ide issue?
I'm interested to know what they tell you.

 

[OilBurner2003]

I've always been taught they should be within 15% of each other. Some say a little less or a little more. 150 doesn't sound devastating. Bu low compared to 185. Does it burn a considerable amount of oil as your user name suggests?
That low cylinder I'd suspect could be cause for your rough idle.
Are they proposing anything to remedy the ide issue?
I'm interested to know what they tell you.

No, it doesn’t burn oil haha. Not really anyway.

They suggested a leak down test, but, it’s a lot more than I as expecting for a simple test I could do at home.

 

[Hoesgottaeat2]

No, it doesn’t burn oil haha. Not really anyway.

They suggested a leak down test, but, it’s a lot more than I as expecting for a simple test I could do at home.

If you don't want to do a tear down, maybe try some additive?

https://www.amazon.com/Restore-00016-8-Cylinder-Restorer-Lubricant/dp/B00HJVEX74

 

[OilBurner2003]

If you don't want to do a tear down, maybe try some additive?

https://www.amazon.com/Restore-00016-8-Cylinder-Restorer-Lubricant/dp/B00HJVEX74

Currently talking to them just to see how much and how long it’d take for a new vortec.

It’s a old truck. Don’t have time to fix it, it’s been beat up and tormented through the woods for about 15 years! If I can get a new vortec in or a rebuild for a decent price, I’ll do that instead just to get it out of the way.

And I’ll take a look at that too.

 

[strutaeng]

Why don't you just buy the leak down test kit? It's around $100 iirc for the OTC.

I wouldn't think those numbers are a huge concern. Unless you are burning oil or smoke coming out of the tailpipe. Are you getting a misfire or codes?

 

[OilBurner2003]

Why don't you just buy the leak down test kit? It's around $100 iirc for the OTC.

I wouldn't think those numbers are a huge concern. Are you getting a misfire or codes?

Truck has had a p0300 for a very long time. I have a hefty list of repairs I have done myself, and I have had three mechanics look it over.

Not one could give me a definitive answer. I would prefer to just be rid of this issue.

I have a leak down test kit myself, but I’m moving to a different state so I no longer have time to do my tests/Repairs.