Cylindar 1,2,3,4
Compression 150,150,135,140
Leakdown 3%,1%,5%,5%

Are those numbers reasonable for a 2.7 liter sleeved 951 engine with 4000 miles? or do I have something to be concerned about? Thanks.

Minh

 

HI Minh,

I'm a little concerened with your lowest reading in #3 and its brother #4. Who did the test? Hmmm..THey seem a little low for a 4000 mile motor. My stock 2.5 had over 200K and the pistons were very loose but my percentage was much tighter than that.

Give me a call at the shop. I'd like to ask a few question if you don't mind.

Take Care!

 

I forgot to mention. After driving 50 miles to the shop, my car was off for about 45 minutes (turned on and idled here and there for a few minutes at a time) before running the compression test and about an hour and a half before the leakdown. Could the results be skewed because the car was not at operating temperature? Thanks.

Minh

 

They should still be closer than that. Perhaps a 5psi diffrence from cold and hot.

#3 is a bit funny...

 

Mihn,

Everything I have read says that all cylinders should be within 10% of each other.

Your #3 is on the ragged edge.

With a new engine you can see differences, but after 2,000 mi everything should be worn in.

I would be concerned with your readings after 2,000 miles. I would venture to say that after 4,000 miles your problem would only get worse and not better. It would be my guess that your engine idles and runs rough, due to #3 not doing its job.

We just installed a remanufactured engine in our Ford Aerostar and it ran rough from day one. After 1,500 miles the shop did a compression check and one cylinder was low. They contacted the engine remanfacturer and they said that after 2,000 miles if it was not within spec. that they would replace it.

The engine gets pulled today.