ADVICE... CHANGING HEADS 98 AWD???

[big JC]

Just bought a 98 awd with 124k on it. It is in excellent condition. I got a p0300 code, it is underpowered, and runs rough. After dickering with it for awhile I took it to a shop that got 20 psi in cyl#6 while driving and tells me the head is bad. my first question would be do I have to worry about the rings or is a valve defiantly the culprit? Changing the head is at the very limit or beyond my skill/tool level. I can get the heads refurbished at a machine shop fir $250 and all the gaskets at wholesale or I can have it done for $1800 and who knows what else they may find. Any advice or tricks I should know on removing the heads myself? Thanx!!

[Kidhauler]

unless you dropped a valve I don't think a bad head could drop the compression that low. I could be wrong and if I am please speak up but I have never seen a engine drop compression that low without the rings being the issue. It might be worth looking at a rebuilt engine If it was me. You could probably get a engine for around $2500 instead of dropping $1800 on just heads and then finding out the bottom end is pooched.

[big JC]

I have read online that valve binding is fairly common for several years including 98 ( s10 forums) and the symptoms associated are what I have to the letter (including cylnider #) It has 60psi at idle but drops down to 20 psi under load ie going up hill Is it safe to assume rings would cause a consistent low psi?

[Kidhauler]

yup rings would cause low pressure all the time. At higher revs it might go up as there is less time for the pressure to leak. I have never heard of a valve binding without a piston quickly sending it to its final resting place. But it is possible I guess the S10 has the same motor so if they have had the problem it stands to reason that could be it.

[big JC]

I found a shop to change and have the heads machined for $1500 I thought about getting a new long block but simply can't afford it With only a 124k on the motor it hopefully has some life left Best case scenario someone overheated the engine and put cold water in it and the head just got f'd up Until they take them off and get a look we won't know I'll post the results

[mdmead]

I think I'd be looking at www.car-parts.com for a complete used engine. Unless you know for sure the problem is in the head, you may find the repair bill pretty steep once they have to tear into the bottom end. A straight R & R may prove cheaper in the long run.

[big JC]

Well got the heads out and the valve seat on cyl # 6 ( the bad one) is totally fried Off to the machine shop they go So obviously running lean on that cylinder What to do ? Get the injectors cleaned or replace or put back together? money is really tight at this point