slammdrider

Ok so me and my dad decided to buy a 94 toyota pickup 4x4 3.0V6 so there are some minor dings and dents and that were capable of fixing our selves. the real problem is that there is knocking coming from the top front of the motor and its burning oil. i was looking through all the paperwork that they had for the truck that goes all the way back to 2001 and found a thing from 2 years ago when it didn't pass emissions and they had it looked at and it shows that there is low compression in the 3 cylinder. my first question would that be the main reason for it burning oil and would that also cause some kind of knocking. my second question is whats the best way to get the compression back up to were its suppose to be and what should the compression be. the motor only has like 120,000 miles on it so i really don't want to have to rebuild it for awhile since there isn't any other problems so far it doesn't leak oil the head gasket is fine. THANKS FOR ANY HELP THAT U CAN PROVIDE!!!!!!!!!!

toyminator2000

Low compression is either really bad rings, bent vavles (not very common on 3.0's) or leaking or blown headgasket (very common on 3.0's

space-junk

iTrader: (1)

i know that my truck, when i bought it a year ago, had 120k on the motor, and it wouldnt pass smog... had low compression on the #3 cylinder as well...
once we got the heads off, we found that the #3 exhaust valve was stuck open... if thats the case, then might as well do a complete rebuild of the top end while your there...

slammdrider

wouldn't there be other signs if the head gasket was leaking or blown i can look at it better tomorrow its dark here now

Stock91

If you had a blown head gasket coolant and oil might be mixing. Not an expert but theres my .02
Has the timing belt been replaced?

abecedarian

that low compression issue may or may not have been fixed since it was 2 years ago so who knows?
Anyhow, depending on how the truck was maintained, 120,000 may mean it's on its last leg. You could do compression tests and leakdown tests to help narrow things down and put the nail in the coffin so to speak, but given the history and the oil burning problem, I'd probably suck it up and rebuild it now, or pull off the infamous 3.4 swap.

thook

Definitely...run a compression test and/or leakdown test to determine if it's valve or ring related. 120k miles and the rings may be fine. But, if the valves were not maintained well...ie ever adjusted...you may have valve problems. A burned valve would cause low compression on one cylinder. Bad seals could cause oil consumption. So, a scenario could be the bottom end is fine, but you need some head work. Get the heads/valves serviced, put it back together, and be good to go for quite a while longer. But, what Abe said is a grand suggestion. Check everything out.

The knocking coming from the top front end of the motor could be timing belt pulley related. Any history on if the timing belt's been serviced at all?

slammdrider

well i went out and looked at some stuff on it since were starting to clean the inside out. im pretty sure that the head gasket does not leak there is no water in the oil nor oil in the antifreeze. i dont know about the timing belt pulleys or not. the motor is only like 4 years old it was a used one that they paid for and had installed but i can look through all the paper work and find out so I'm leaning towards either the valves or the rings. we just want it to last like at least one more year and then we were going to have the whole thing rebuilt with some upgraded parts hopefully

Quick question what is the correct compression for the cylinders