smoke after warm up...
 

First of all, it's an 89...so renix 4.0L.

Drove it to work the other day and ran into a bit of trouble. It's smoking like crazy after warm up, but after it cooled down it didn't smoke upon the next start up. Started again after it got warm.

Now, it doesn't smell like burning oil. It is gray'ish smoke. No miss at all. Compression test shows 150'ish psi per cylinder. Plugs, cap, rotor, wires are all new within the last few hundred miles. CTS and air temp sensor are both new. No oil in coolant, no coolant in oil.

Insights? I'm a little stumped right now.

It could possibly be your valve stem seals. I had it happen to mine and my brothers 240sx's. When the valve stem seals start to go the allow oil past the seal into the combustion chambers under high vacuum , like getting on the motor under load and such.

I'd pull your plugs and check for signs of burning oil.

If your compression is good all the way across the board and the headgasket is good, your valvestem seals are the likely culprit.

I agree with him^^^^^ how is your oil level sitting?

with those 4.0 liters the transmission, if it's leaking out the front, leaks on the exhaust and causes it to smoke. That's what happened to mine as I blew the O ring on the transmission pump. You really won't notice it as it'll only lead for a bit after driving it or when it's started.

x2 on the valve stem seals

Ordered a set of valve seals, probably change them out over the weekend.

Have fun changing them, They are kind of a P.I.T.A a valve spring compressor helps in compressiong the spring enough to remove the collets ( retainers)

There is also a fitting you can atach to an air compressor and screw into the sparkplug hole and pressurize the cylinder to keep the valve from falling into the block.

I personally just use a piece of thin clothesline style rope and feed it through the sparkplug hole until i feel there is a good amount in the cylinder ( remember to leave alot hanging out of the hole so you can remove it again) then I rotate the engine by hand until the rope is compressed against the valves, that will hold them from falling in the block on you.

Just giving you some advice cause I'm not sure if you have ever changed valve stem seals before.

I've done them before, but not on the Jeep and I've had the head off all the other times. I've got the fitting for the spark plug hole already, compression tester has a normal air line fitting on the gauge end :)

I built a spring compressor that worked on the last couple cars, hopefully I can adapt it to work on this one also. Good news is that it's not a DD....bad news is that I really wanted to take it out wheeling for the first time over the weekend. Oh well, maybe next weekend.

Got motivated and did it last night, smoke is gone. Well worth the 2 1/2 hours of work.

It was fairly easy, the compressor I built a few years back worked wonderfully until I got to the last spring in the back. It took a little maneuvering and swearing, but I got it done. Test drive was great, and I had a bit of a backfire when I let off the gas before that has now disappeared. I'm guessing it was consuming a bit more oil than I thought...

Tightened up the oil pan and got rid of the leak from the bottom. So it was a good night for sure. Glad it was an easy fix since the gasket is new, and I really despised doing it the first time.

Awesome bro glad to hear its fixed :thumbup1:

Any pics of the homemade spring compressor you made by chance? I'd like to build one if its not to much work, otherwise I'll probably just buy one lol

I'll try to snap some pictures of the compressor. It's a really simple setup, just a couple pieces of flat bar and a piece of pipe.

Drove it to work and back and didn't use any oil at all. There wasn't a drop on the ground either.

Good timing as I'm considering trying to trade it off for a Comanche or something.