hi guys, i just did a compression test on my 2000 4runner. Good readings across all cylinders except for #4- its at 150. Are there any good engine conditioner type products out there that may help this problem out? BTW- what is compression supposed to be at normally?

 

im getting 175 on the rest of the cylinders

 

Then the rest of your cylinders are compensating.

Hmmm, well whatever the norm is, you still have a 25PSI deficit...

How many times was the test done? Are you sure the compression tester is accurate? I would test it again on another Comp Tester. Just to be sure.

 

it was done at a dealership- i didnt feel the need to question their equipment

 

175 is just like brand new. at 150 youre down about 12-13%, really not that bad, but id get a leakdown test done. this can tell you a lot more, especially wether or not its going through the crank case, etc. 5% on the leakdown is like brand new, my 140k engine was at 10%, still very good, except of coarse for #3, wich is the one i had let go....it was leaking 30% through the crank case (bad ring i suspect) and @150 on compression while the others were at 170 (remember 140,000 miles on it). but anyways, a leakdown test will tell you a lot more about your engine then a compression test. oh, any mods? and are you under warranty? and did anything funny happen to make you aware something was up? thanks again, im just so damn curious.....

 

Ok, well fine. But, why were they testing the compression in the first place. In other words, what caused you to have the test at the Stealership? Pinging? Loss of power? It would help to know mileage, mods, past history.

Hey, more power to you on never questioning dealer equipment. As we all know, the stealer never screws anything up.

 

Good compression values are readings across all cylinders that are within ~10% of one another. The minimum value for compression is right around 125 psi. How hard do you drive your vehicle, how many miles do you have on it, and do you have an SC?

As far as engine conditioners I have heard of very good first hand reports of a product called Rislone it helped a person restore compression in 2 cylinders. They have a website and sell it online or you can find a local place through their dealer locator.

 

sorry for being so vague. Its a 2000 with 70,000 km's (approx 42,000 miles) I just bought the vehicle and got the previous owner to do an inspection on it. The 150 was on cylinder #4, 1-3 and #6 all had 175, while #5 was at 165. It has no mods (yet ) and the wifey drives it pretty easy. Appreciate all the help guys

 

that means its still under factory warranty right? mines so "old" i have no idea about the warranty, thanks again. im sorry if im being a pushy jerk.......you cant tell any power loss either? maybe you could relay my question to the previous owner about the :
"and did anything funny happen to make you aware something was up? "
thanks, jake

 

Hmm, well I've heard of a car that was driven very easily with irregular compression that regained it's compression when Rislone was used. Are you very set on the vehicle? I guess the low value would make me wonder, but at the same time if you think it wasn't driven hard it's probably not that big a deal since 150 psi is still good. Here's the link for the Rislone:
http://www.rislone.com/engine.htm