PDXJ40

Hi all. New here and not super experienced. I bought a '92 XJ 4.0 that (supposedly) only needed a fuel pump. It did not start and I don't know how long it's been sitting since it last ran. After I replaced the fuel pump, I tried starting the car and the engine was turning over, but then all of a sudden the dipstick popped out and smoke started coming out of the dipstick hole. This happened both before and after an oil change and oil filter replacement. I don't think any oil was coming out of the hole, just smoke. Any ideas as to why this is happening?

tech

What happens if you take the oil cap off and crank the engine ?

PDXJ40

Haven't tried that... That's something I could do. But wouldn't oil spurt out with the cap off?

tech

maybe , it sounds like the rings may be stuck and the engine has a lot of blow by that's the compression going right by the rings . you mite want to put some trans oil in the cylinders and let it sit over night before you try to start it again .

s346k

or there’s a mud dobber nest in a ccv line...something crankcase ventilation related.

Bugout4x4

Yep... "Blow by". Compression is pressurizing the crankcase for some reason. Either a blockage in the Crankcase ventilation system like s346k mentioned or a massive compression leak. And you are right... The only way to see how bad it is would be to remove the oil fill cap and see how much there really is. If it's puffing good there is a major issue for sure.

tech

It looks like everyone over looked that the engine haven't run , I think it needs to soak the rings in trans oil before it's started .

PDXJ40

Stuck piston rings make sense. I think I will go ahead and let them soak overnight. Is trans oil the best fluid for the job? I've also read people use seafoam, diesel, Marvel's Mystery Oil, penetrating oil, or a combination of these. I'd like to use the most aggressive treatment. What do you guys think?

Tbone289

MMO would be my fluid of choice. It has an oil base, rather than a straight solvent like Seafoam. If you need something stronger, penetrating oil would be OK.

Be sure that the CCV system has no clogs in it before assuming this is due to stuck rings.

Bugout4x4

vvvvvvvvv I agree with T Bone. And you want to put it down the plug holes because putting it in the intake will do no good at all and could cause it harm.

PDXJ40

Alright sounds good, thanks for all your advice guys. I think I'll first replace that CCV elbow and hose. If that's fine I'll do an MMO soak with a generous amount of oil (maybe with a bit of penetrating oil mixed in) for a good 24 hours and try starting it afterward. I'm really hoping it's the CCV valve or stuck piston rings rather than something deeper.

PDXJ40

How much fluid would you guys put down the plug holes and into the cylinders to free up the rings? I poured almost a liter down one of the plug holes because I read elsewhere that you should fill until you see the fluid flowing back out... Now I'm worried that was way too much.

Bugout4x4

Don't turn that engine over with the starter with that much in it. It will hydrolock and crack the head or loosen the gasket .

But you haven't hurt anything yet as long as you don't try to put the plugs back in and start it with that much in there. I would think about a half a cup per cylinder would be enough. Then let it soak and drain down past the rings for a couple days.

After this you will want to turn it over BY HAND with the plugs still out at least two full revolutions before you put the plugs back in and try to start it. It is important that there is no more, or very little liquid left in the cylinders before it is turned over fast with the starter.

Did you check the Crankcase ventilation? Was it clear?

s346k

let it sit a day or so and crank it over with the spark plugs out. having too much liquid in the combustion chamber will hydro lock it and most likely bend a connecting rod.

Bugout4x4

Once again... Just said that... lol

Curious? do you read any of the other replies that have already been shared at all?