Cadillac SRX 05 low compression on #6 cylinder

SAHAG41

MEMBER
2005 CADILLAC SRX
3.6L
V6
AWD
AUTOMATIC
107,000 MILES

Compression test shows low compression#6 cylinder. With new heads would there be blow back to lower block(pistons, rings, seals} are there any products that may restore compression, since vehicle runs smooth with no loss of power. Had check engine light on that indicated misfire, bank 2 downstream oxygen sensor and mass air flow sensor. Mechanic said that with replacement of those parts with new air filter the problem would not be fixed.

6 Replies

RACEFAN966

MECHANIC
5,029 POSTS

I am sorry to say that if it is really low on compression there is no buy it in the store fix. It will need to be fixed. If it is rings then it will be a rebuild if it is valves then a valve job is in order. There is no cheap in a can fix. Your mechanic is right those items will not fix low compression. Sorry.

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Saturday, June 21st, 2014 AT 6:51 AM

SAHAG41

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8 POSTS

The heads would include new valves. I know that there may be a problem with piytons and rings: however my direct question was, "will there be increased blow back"

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Saturday, June 21st, 2014 AT 9:07 AM

SAHAG41

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8 POSTS

I am vague on the answer. Will new heads which will include the valves cause any blowback?

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Saturday, June 21st, 2014 AT 9:11 AM

RACEFAN966

MECHANIC
5,029 POSTS

This all depends on the condition of the lower end. If the rings are weak to start with and a rebuild was in order and all that was done was the heads then yes it can. In other words you now have improved the compression with the heads and the valves now 100 percent seal it will put strain on the lower end. I prefer to do a compression test first then once the heads are off if there is no evidence that the valves are burned and didn't cause the low compression then I recommend a complete overhaul. If all you decide to do is the heads then you need to be easier on the engine for at least the first 500 miles or you will put stress on the lower end and blow rings. I hope this better answers your question.

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Tuesday, June 24th, 2014 AT 8:29 AM

SAHAG41