ComancheFan Posted September 24, 2018 Share Posted September 24, 2018 1987 Cherokee 4wd automatic 4.0. On a cold start up there is a ton of white smoke coming from the exhaust manifold area. When it’s off there is a slow leak of antifreeze. The leak is underneath the intake but above the freeze plugs. I checked the oil and it’s not milky. I’m hopping someone here has delt with this issue before so I know if I should part out this one or fix it. Maybe there is a temp sensor under the intake that could be leaking? Link to comment Share on other sites More sharing options...
Wounded_Fighter Posted September 24, 2018 Share Posted September 24, 2018 could you provide a picture of where its leaking from on your jeep? Sounds like just a gasket met its time...? Link to comment Share on other sites More sharing options...
ComancheFan Posted September 24, 2018 Author Share Posted September 24, 2018 Now that I think about it. It may be a head gasket. The water pump pully is froZen and there is no serpentine belt. Link to comment Share on other sites More sharing options...
ComancheFan Posted September 24, 2018 Author Share Posted September 24, 2018 I can’t see where it’s leaking because the front diff is in the way. It’s leaking on the the exhaust manifold but it’s under the intake. As soon as I turn it on it’s a cloud of white smoke. I’m thinking it’s a head gasket but I would hate to pull it apart to find that’s not it. Link to comment Share on other sites More sharing options...
gogmorgo Posted September 24, 2018 Share Posted September 24, 2018 Bad freeze plug seems most likely to me. Pulling the manifolds will get you a better look, and you'll want to do that anyhow if you're going to end up pulling the head. Head gaskets do sometimes fail without cross-contaminating fluids, although it's not particularly common. A compression test wouldn't hurt, especially if it's been run for quite a while with no water pump; that's a pretty important part. Link to comment Share on other sites More sharing options...
ComancheFan Posted September 25, 2018 Author Share Posted September 25, 2018 I will pull the intake and exhaust manifold off and see where I’m at. I have put over 350k miles on my Comanche without needing to pull the head but without a water pump it’s hard to say. Incase the head is warped or cracked what year 4.0 heads should bolt on without modification? Link to comment Share on other sites More sharing options...
Eagle Posted September 25, 2018 Share Posted September 25, 2018 Without modification? 1987 thru 1990. Link to comment Share on other sites More sharing options...
yxmj Posted September 25, 2018 Share Posted September 25, 2018 Don't shoot the horse yet....head will probably be good....a gasket might be all you need... Link to comment Share on other sites More sharing options...
ComancheFan Posted September 25, 2018 Author Share Posted September 25, 2018 Yeah hopefully It’s just the gasket. This was a impulse buy. It needs brakes, rust fixed around the windshield, a new windshield, water pump and belt rear lift gate aligned, driver floor pan. It’s a Chief with 4wd and for $300 I couldn’t pass it up and I didn’t want to see it end up getting crushed. Link to comment Share on other sites More sharing options...
gogmorgo Posted September 25, 2018 Share Posted September 25, 2018 Hopefully it goes better for you than it did for me recently... I picked up a '91 2.5 2wd shortbed in great shape for what I thought was a price I couldn't pass up, caveat was it had an "overheating problem". Figured it was due to the super crusty radiator. After further investigation it turns out the coolant passages in head were plugged up (looks like stop leak...), which created a hot spot that burnt the gasket and melted a piston. Doing a compression check before you pull the head is still a good idea. Also, my money's still on a bad freeze plug. Link to comment Share on other sites More sharing options...
ComancheFan Posted September 26, 2018 Author Share Posted September 26, 2018 I just pressure tested the Jeep with the manifold off. At 25psi the only leak is the lower radiator hose. I found where the white smoke is comeing from. There is a pinhole in the brake line that connects to a vaccume line and goes to the canaster under the coolant resivor. I’ll put pictures so you can see what I’m talking about. I'm wondering if I can just cut the brake line and put a longer piece of vaccume line or is it a high pressure line? Link to comment Share on other sites More sharing options...
ComancheFan Posted September 26, 2018 Author Share Posted September 26, 2018 https://ibb.co/fH0PCUhttps://ibb.co/eyJBsU here's the pictures of the Brake line and the canister it runs to. Link to comment Share on other sites More sharing options...
SVPete Posted September 26, 2018 Share Posted September 26, 2018 The rusty steel line in the center of your photo is not a brake line. Pretty sure that is the fuel tank vent line that runs to your charcoal canister using the rubber line connected to it. If that is creating the white smoke......it would get me scared. Can you cut it and replace the rubber hose....yes. It is not high pressure. It should only carry vapor. Link to comment Share on other sites More sharing options...
ComancheFan Posted September 26, 2018 Author Share Posted September 26, 2018 That’s very strange. It only shoots fluid out when I push the brake petal or if the Jeep is running. Link to comment Share on other sites More sharing options...
gogmorgo Posted September 27, 2018 Share Posted September 27, 2018 Something is not as it seems here. You might want to trace that line really well to confirm its function. It may well be a brake line, but I suspect it is in fact a fuel tank vent line. But there really shouldn't be anything connecting it to the brake system. Hypothetically they both are connected by vacuum lines, via the brake booster, but I suspect you'd have extremely worse symptoms if somehow the two were causing problems with each other. Pop the vacuum line off the brake booster and you should have severed any connection between the two. 25 psi is higher than the cooling system is rated for. You shouldn't exceed cap pressure when you can avoid it. 14 psi in a Renix I think? Not sure, hopefully someone else confirms. But it sounds like you've located the coolant leak? Link to comment Share on other sites More sharing options...
ComancheFan Posted September 27, 2018 Author Share Posted September 27, 2018 The Jeep came with new hoses and a water pump so I went ahead and installed them and there is no more coolant leaks. The source from the smoke appears to be from the fuel vapor line. When I first noticed the leak in the line the intake was off so the booster was already disconnected. Also probably unrelated but the brake light stays on and the brakes go to the floor on startup. Link to comment Share on other sites More sharing options...
ComancheFan Posted September 27, 2018 Author Share Posted September 27, 2018 6 hours ago, gogmorgo said: Something is not as it seems here. You might want to trace that line really well to confirm its function. It may well be a brake line, but I suspect it is in fact a fuel tank vent line. But there really shouldn't be anything connecting it to the brake system. Hypothetically they both are connected by vacuum lines, via the brake booster, but I suspect you'd have extremely worse symptoms if somehow the two were causing problems with each other. Pop the vacuum line off the brake booster and you should have severed any connection between the two. 25 psi is higher than the cooling system is rated for. You shouldn't exceed cap pressure when you can avoid it. 14 psi in a Renix I think? Not sure, hopefully someone else confirms. But it sounds like you've located the coolant leak? Yes I thought it was a freeze plug or head because of the way it was smoking and I was confused as to how it wasn’t leaking anywhere but the lower radiator hose so I kept adding pressure sure the leak would appear. Link to comment Share on other sites More sharing options...
gogmorgo Posted September 27, 2018 Share Posted September 27, 2018 Coolant spraying onto hot exhaust could also create steam? Link to comment Share on other sites More sharing options...
ComancheFan Posted September 27, 2018 Author Share Posted September 27, 2018 1 hour ago, gogmorgo said: Coolant spraying onto hot exhaust could also create steam? Yes it could and it’s what I thought it was. I pulled the intake off and pressure tested the system to find out it was just the lower radiator hose leaking. I changed the hose and water pump no more coolant leaks. What I need to figure out is why I have brake fluid coming out of a pinhole in the fuel tank vent line and spraying on the exhaust manifold. Link to comment Share on other sites More sharing options...
gogmorgo Posted September 27, 2018 Share Posted September 27, 2018 Stop. Go back. That "brake line" is a completely separate issue. It has zero to do with the cooling system. If it is a brake line, it has zero to do with your fuel tank vents. And the charcoal canister is on the complete opposite side of the engine from the exhaust manifold, so there's no possible way it's squirting anything onto it without thoroughly coating the entire engine bay, and your photos show zero evidence of that. You need to slow down and figure out what you're looking at, or no one will be able to help. And I say that because you're telling us you're experiencing problems that cannot possibly exist. You've got a 30 year old truck that could've had anything done to it over a long life, so there's no guarantee anything on it is still factory. You need to know what's going on with it. It's also not a new truck by any means, so it's quite possible there are a whole whack of problems with it that have nothing to do with each other. A leaking pipe, hose, whatever, is a problem that should be fixed. You need to establish what the line is for, what should be in it, and then what is leaking out of it; then if that's something that shouldn't be in it, why it's coming out of it. Link to comment Share on other sites More sharing options...
ComancheFan Posted September 27, 2018 Author Share Posted September 27, 2018 Ok sorry if I'm jumping all over the place with problem I’m having. My original problem was a coolant leak and white smoke coming from the exhaust manifold. The coolant leak has been resolved. I then discovered the white smoke has nothing to do with the coolant leak. I then found a pinhole in a hardline leaking what appeared to be brake fluid. What I saw apon further inspection was that the rear brake line behind the vent tube is leaking and not the vent line. I have replaced the brake line and there are no more leaks and no more smoke. I appreciate the help and like you said there can be all kinds of problems with a 30 year old vehicle. From service records I was able to see it was driven in New York 1986-2001 1-190k Miles. Then it spent 2002-current in Florida 193k-220k miles. Link to comment Share on other sites More sharing options...
SVPete Posted September 28, 2018 Share Posted September 28, 2018 And no more brake pedal to the floor I hope? Link to comment Share on other sites More sharing options...
ComancheFan Posted September 28, 2018 Author Share Posted September 28, 2018 Right. I now have functioning brakes. Hopefully Sunday I will get arround to putting a new belt on. Link to comment Share on other sites More sharing options...
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