View Full Version : 86 s10 2.5 motor problems :(

10-21-2009, 10:34 PM
SO i have an 86 CHevy S10 with the 2.5 4cyl. 4-Sp. man. trans.

It all started when my truck started "misfiring" awhile back...
changed cap, rotor, plugs, wires, coil, etc. still misfired so i changed the whole distributor. that helped alittle.
But when it started misfiring a little after it started puffing blue smoke out.
Then I got stranded and had to drive the hurt S10. Heard ticking/knocking from under the hood. got to my location, pulled the valve cover and one of the rockers was loose, very loose. thing is the bolt/stud was torqued to specs.
From then it emitted insane amounts of blue smoke along with the "misfire" and rocker clattering noise.
No pushrods are bent and washers and rockers checked out okay.
When i pulled the head a chunk of gasket was missing from between the first 2 cylinders closest to radiator. loose valve is on "3rd" cyl. I think on exhaust side.

I was told by a guy at local shop that it was a lifter and that i needed my engine rebuilt. His opinion was based off what i just said above.

I just wanna know whats wrong. :(

Someone please help me.
Thanks for any help. :)

Cyanide Jello
10-22-2009, 12:23 AM
You pulled the head correct? Did you notice any bent valves?

You may have seized up a lifter... Thats what it sounds like... In which case it probably ate the camshaft and the lifter...

Rebuild the head or buy a reman. head and get a new cam and see what it does...

But since you're down that far you might as well either swap in a new engine or just rebuild what you got... Its up to you and how deep your wallet is...

10-22-2009, 08:03 PM
Since GM's 4 bangers are bad about lifters and going by what you said I agree with both doug and your mechanic. ATLEAST do a cam, new lifters and a rebuilt head.

lil red s10
10-22-2009, 08:51 PM
yup... blue smoke means it'd burning oil. could it also be rings??

10-23-2009, 08:52 PM
Could it also be rings? cylinder walls are smooth with no nicks or anything. lots n lots of build-up of carbon in combustion chamber.

I shined light into where pushrods go and where the problem is, its dry. the other ones have oil in em just not the bad one.

Would anyone on here be selling a 2.5 s10 motor? I cant seem to find any for sale here.

Id like to stick with same motor. no conversions at this time... sorry :(

Thanks for your help guys. i really appreciate it. :)

lil red s10
10-23-2009, 08:59 PM
not sure. but blue oil is burning oil. may not be much. just enuff to turn the exhaust a blueish tint.

10-23-2009, 11:44 PM
check www.craigslist.org

i could get one.. but it would be $150 (runs great.. my old motor actually) but shipping or whatever to whereever you are would be more than a 2.5 is worth

10-24-2009, 09:23 PM
hmmm how many miles does your 2.5 have on it?
and my zip is 57719 in SD would you be able to get me a shipping quote? im interested in your motor.

10-24-2009, 09:46 PM
couldnt even begin to tell you how many miles are on it.. its my old motor.. but its not my motor now.. buddy of mine ownes it.. bought it for his s10.. then sold his s10.. he would want $150 for it.. but again i wouldnt fool with shipping a motor you can get around your area for the same price

11-27-2009, 11:20 PM
the 2.5s are notorious for high mileage timing problems. breaking/stretching timing chains.

lil brown 2.5
12-27-2009, 10:08 PM
solo if your needing a head i have one that is in good shape for an 86. my motor and system has been upgraded to a 87+ throttlebody setup and i dont need this head.
i had the correct head that went to my 86 and it was cracked, i compaired the casting # to my old 86 head and they are the same. i dont wanna pitch i because older duke heads like this are getting harder to find.