Low compression on one side of engine. What does this mean?
 

I have 50 compression on right side of 2003 Hummer H2 engine and 150 in the left. Dealer recommends I replace engine. What would cause one side of the engine to have low compression? Would it be worth having a person take the engine apart to give it a good check? I am looking at remanufactured engines now.

how many cylinders are low? 150isn't very high either.... 50 is dead...


what about the other 6?

You could just have a bad head or a burnt valve.


You have a lot of missing variables that mean the difference of a top job vs a new motor.

Thanks for replying
 

The dealership told me 170 on the side with 1, 3, 5, and 7. The compression on the other side 2, 4, 6 and 8 is 50.

This is what the dealership put on the receipt:

On initial diagnosis found excessive back pressure in right converter of greater than 5PSI. Should be below .5 PSI. Replaced catalytic converter and retested. Found engine internal noise. Performed compression test and found right bank below spec test at 60 to 80 PSI. Left bank at 170 PSI. Unable to determine what failed first, engine or converter. Recommend engine at this time.

I've never seen an entire bank of cyls go bad.... ever.... Did they do a cyl leakdown test or no?

I personally would want more info because sitting here second guessing what you wrote makes me think head.... not engine.

Thanks for your reply. I have been sucking a lot of oil yet no leak. That is why they say maybe its the pistons or valves. Since the dealer looked at it and made the recommendation for a new engine I am going with a remanufactured engine.

How many miles?

I guess he really didn't want any help after all. Haha. Hey, just throw money at it. It'll be fine.

Thank you everyone who replied. I am going with a re-manufactured engine as the dealer advised me to do. I am keeping my hummer for life and want the best for it. I am not wasting money on someone opening up the engine and then trying to fix it for something else to go wrong.

Nancy

I love buying parts from people w/ those same thoughts... I'll give you $100 for your junk motor.

Just throwing this out there from looking at your pic and its file name. If your female and your the only one dealing w/ this shop...I'd tell'em your keeping that motor. Make sure some tech isn't ****ing you and planning on having a nice free motor. Something isn't right w/ an entire bank dead. I'll still buy that motor off you for $100!