vh2q

Well 84 Jeep Wagoneer 2.8 V6 was running hot, coolant was low. Refilled coolant, found a small leak at heater, fixed that too. Car was running cool and running great. But coolant low again when I checked it after about 40 miles. To cut a long story short, checked my dipstick and found milky oil, and plenty of it. Obviously that's where the coolant was going. I believe it's the dreaded intake gasket(s). Only 45K on this motor.

Can someone point me to instructions as to how to replace these gaskets. I believe it's pretty straightforward but still, it's less worrying when you have the instructions. I don't want to have to drive the vehicle to the shop in this condition. Shop is 17 miles from me.

Thanks!

RocketMouse

I would also think pretty straight forward on one of those. Have you tried a FSM for your year/model yet?

vh2q

I found this

http://workshop-manuals.com/jeep/wag...tins/page_544/

but it's rather terse. Anyway it's better than nothing. Hopefully it's the intake manifold gasket and not a head gasket. From the way it was running (great) I don't think it was a head gasket. I guess the intake manifold has to come off either way. Will check the plugs and cylinders to see if there is any water in there but I doubt it.

vh2q

I got the intake manifold off and all the mating surfaces cleaned up. Wasn't fun due to emissions clutter and poor layout .. you have to remove a/c compressor, carb, distributor, coil, coil bracket, EGR valve, and a whole bunch of wiring and plumbing; many of the fasteners are barely reachable.

I found one of the inlet manifold bolts quite loose and a couple others came out real easy. Only the corners required any grunt. The gasket was torn across the upper web on one side around the water port and the gasket and head surface around all four of the water ports looked dubious. It was stuck really well around the fuel ports but not so well around the water ports. The aluminum on the manifold is a little pitted around the water ports as well. So I THINK that's the root cause. I torqued the head bolts and a couple of them moved a tiny bit on the right bank. So I pulled the plugs on that bank and found two of them had awfully white insulators, the third was a tinge dirtier. All of the plugs had about the same coloration on the metal electrode with no oily or sooty deposits at all.

So before I put everything back I need to be sure it's not the head gasket on that side. There is a lot of water in the oil but no oil in the water. And the car was running great with no steam from the exhaust, and cool provided I kept the coolant topped up. It got very warm but not hot at one point when this saga began, and the coolant was very low when checked.

How does one make sure, short of pulling the head(s), that the gasket(s) are sound? I would think that a bad head gasket would put oil in the water as well as water in the oil. I only have water in the oil.

If it does come down to pulling the head, any tips? The valves are self adjusting. Do I need to put the pushrods back in the same order? The exhaust manifold and the accessory mounting brackets on the front of the head look like the biggest headache.

Bugout4x4

Bad head gaskets can do one or the other and not both sometimes. My recent bad head gasket did neither... It was just consuming more water than it should have. Then I found the head was cracked too. Honestly if it were mine I would go ahead and tear the heads off too... You have it half done at this point. But white plugs definitely indicate it's probably burning coolant in those cylinders.

RocketMouse

What others in this thread have said is true.... Your question about pulling the heads, I would release/loosen the bolts a little at a time (all of them) not just loosen and remove one bolt at a time. Same goes for the tightening pattern when you re-install them.
As for the push rods... absolutely keep them in the same order. Easiest way people do it (self included) is get yourself a good size piece of cardboard box. with a sharpie, draw an arrow facing one direction (indicating front of engine)... then as you take each one out, poke it through the cardboard. Do that for each cylinder in a row down both sides. Then set it off to the side where it won't get knocked into until you're ready for it again. Low-tech problem solved.

As for short of pulling the heads... no other way I know of. That's where the channels are. What you're doing is praying for it to be a bad head gasket and not a cracked head. But far as I know, pulling them is the only way to fully inspect the root cause.
the other possibility is you could have a warped head too. Not cracked, but won't sit flush. It doesn't take very much at all of those mating surfaces to be off before it starts causing major problems.

vh2q

Is a compression test not definitive? If the compression is good could the water still have gotten into the oil in large volume (about a gallon of it).

firebane

Compression test is only for seeing if the volume of air is good.If your HG is bad it can get into the cylinders and get past the rings.

vh2q

So I pulled all the plugs and they were all nice and clean but no 3 was the cleanest. Well after racking my brain I decided to make a spark plug hole adapter that would screw into a plug hole and hook up to my compressor via the quick disconnect coupling. That took a couple of hours on the lathe and mill but I got it done. I then hooked up to cyl no 3 the one with the whitest plug. Cranked 80 psi in there. No leak. Hooked up to adjacent no 1 and hear some hissing from crankcase (near cam). Figured that's blowby. So I am going with the theory that it was just the intake manifold gasket that dumped all that water into my crankcase. A head gasket would have had to be really badly blown to get that much water into the oil in so few miles, and there was no loss of performance and I am not finding evidence of a bad head gasket with the compressor method.

Will bolt it back together Tuesday, NAPA was closed today when I went to fetch my gaskets. Hopefully the bearings etc are OK.

firebane

If it came from the intake ensure any bolts going into a water jacket have thread sealant on them... this is not rtv

vh2q

I intend to use Versachem Gasket Sealant 2 on all the bolt threads ... unless you guys think that's a bad choice. I will use that copper spray-on gasket adhesive on the back of the intake manifold gaskets. Black RTV on the China walls and the seams where the manifold and the head join. And maybe a little RTV on the front of the gaskets around the water passages?

vh2q

I can't find the correct carb mounting gasket/plate (with the heater .. this is a CA car) .. apparently NLA. But I live in a warm part of the country so is there any downside to going with a standard (non heated) plate?

vh2q

Some final questions as I bolt this back together:

1. There is an air injection manifold that runs in the valley. One of the pipes wraps around the back of the EGR valve and is hooked up to nothing. The other end of that same pipe is blanked off toward the front of the motor. Is this correct or did some prior mechanic remove some plumbing?

2. The same air injection manifold has a tab that is supposed to be bolted to the front valve cover fastener .. is this supposed to go under the bolt head, or is there a second nut to hold this in place?

3. There is an electrical sensor in the rear of the RHS head ... behind cyl no 5. It has two connectors but nothing connected there. What is it and what is it supposed to connect to?

Thanks!

vh2q

Well could not wait forever for replies, buttoned it up (what a pita this job is, the carb has 3 linkages, 5 vacuum lines, and 4 electrical hookups, and no easy way to access the hold-down nuts). I took it for a 50 mile run and it runs great with no water in the oil and steady oil pressure and water temp.

I have to say this is one of the worst motors I have had the misfortune to work on. The motor is buried in wires and plumbing, and you can't get at the plugs let alone all of the bolts. Shame on GM for that. Also shame on them for designing a motor that suffers this inlet manifold failure problem with regularity, has transfer case reliability problems, as well as rear main seal leaks, valve cover leaks, and induction manifold oil leaks. Ruins an otherwise durable vehicle.

tjwalker

The 2.8 is one of my least favorite engines.