Im a little depressed on this Tuesday morning, and I'll tell you why. About 3 weeks ago I bought this '91 3.0 5sp 4runner with 169k miles for $1200. The guy said it had a blown headgasket and a bad clutch. So I figured heck, I did the headgasket on my '94, so I can do that again, and how hard could a clutch be. Well, last week I got the clutch done and last night I finished putting the engine back together with rebuilt heads and a new headgasket in. I was excited to see how this little puppy would run. So at about midnight last night I fired her up and once the fuel got pumped back into the lines she started purring beautifully, except for one major thing. SMOKE, and lots of it, blowing out of the exhaust pipe. I drove it around the neighborhood for a few minutes to see if it would stop, but it didn't. It drove pretty well, but you could tell on the hills that it didn't have full power.

So, Im assuming now that one or more of the piston rings are bad. I didn't feel like doing a compression test last night or this morning but I'll do that tonight.

The question I have for you all is this: Can you replace the piston rings without pulling the engine out? Can I get to them from below? Is it possible to leave the crankshaft in place and take the piston out, replace the rings, and put it back in? It seems like the best thing to normally do is to rebore the cylinders when you replace rings, but I really really don't want to redo all the work I've done over the last three weeks and pull the engine. Also, do you think that if the previous owner drove on a blown headgasket too long that it could have ruined the piston ring in that cylinder?

Thanks for you help on this.

Will

 

Yes, you can do the rings w/o pulling the crank.........but the pistons have to go out the top (pull the heads)

 

its worth putting the work in to get it fixed right now as opposed to doing half the work and having to do the rest at some other point.

I would personally pull it and just rebuild the whole thing so you know you'll get a lot more miles out of it.

Its probably not worth replacing the rings without atleast honing the cyls. At that mileage you've probably got some scoring, and you're going to continue to burn oil if theres any scoring on the cyl walls.

 

Well, you've already got one headache on your hand so don't create another... Just pull the engine and fix it right. I know plenty of people to replace rings without pulling the engine and 90% of the time they wish they just pulled it and did it right.

 

Do you know what it was burning? Coolant or oil?

I replaced an oil cooled Diesel HG last week and it took about 2 hours to burn off all the remainig oil in the muffler/exhaust.

Maybe, just maybe you'll get lucky and find it needs more run time (fingers crossed).

Pull a plug to see if it's wet and what it's wet with.

 

slc - what kinda diesel was it you were working on whose HG popped?

 

The smoke didn't really smell like anything. Im going to run it tonight and then look at the plugs and do compression test. You give me hope though SLC.

 

I prefer leakdown, if you've got the equipment.. It'd help diagnose rings for sure.

 

Are you sure it just wasn't from being cold?

Rob

 

It's an oil cooled Deutz engine, largely used in Agricultural/Industrial enviroments.

We use them in our TUG's and De-Ice Trucks at the Airport, we have an assortment of diesels ranging from: Power Stroke, Cummins, Navistar 7.3 TD, Mercedes, Detroit, and Perkins.

 

Yep, it was quite a bit of smoke. Lots more than what it looks like on a cold morning.

 

what color?

 

It was pretty white

 

I would guess it's like SLC suggested. If it's white then it's not oil. Oil burns blue. It sounds like it's coolant. Try running it a while and watch the temp. and see if it burns off. It could take a while.

 

SLC, your the man. You were right. I let her idle for about 20 minutes and the smoke slowly went away. YES, that makes me happy. I drove her around the neighborhood (with the hood still off of course) and she is driving great! There is a little clicky noise coming from the right, back side of the engine, but Im just happy I won't have to take that sucker apart again to do a major overhaul.

 

i got a dumb ???you goto pull the motor out to hone the cyl ???and is honing that big steel brush looking thing????

 

You can hone the cylinder in place but it would be difficult. Considering that you'd have to remove the head and then remove the oil pan, un-bolt the rod from the crank and then pull the piston and rod up through the top.
THEN - there maybe that ridge at the top of the cylinder that would need to be removed to get the piston out. then you could hone the cylinder with
flat stones first and then a big bottle type brush with small stones to cross-hatch the cylinder bore.

I'd pull the engine and do this where there is room and do it right !


I replaced a head gasket on a Honda Prelude 2 weeks ago and once I got it runnig again - it smoked like a Fog Hat concert for about 45 minutes - the exhaust header, cat and muffler must have been full of anti-freeze.
Runs like a top now ! I have a grand total of $700.00 in my new daily driver and I'm getting 34 mpg. It's pretty quick too ! Well - a LOT faster than my 4 cylinder 4 runner.

 

Sweet!! Glad it seems ok...a little better solution than pulling the engine!

I'd SeaFoam it to get any residiual junk out and then remove a plug to assess the running condition.

I'm not familiar with the 3.0 but the clicking is probably a VSV or relay.

*sidenote* are you new to wheeling?? Here's a new UT club...www.mountainyoats.com

 

Just an idea...
There's this really good stuff called Auto-RX I've used on both my high mileage 4rnr's that works real well for cleaning out the crankcase, too. I used it because it was real safe, and the oil change interval during cleaning and rinsing was more extended.