My poor 4.0!!! Help!

[35Remmy]

OK...so I have been getting the gurgling/dripping sound from heater core area bad the past few days.

Check coolant yesterday, it was down to the fins and reservoir was empty Added, burped, topped off.

Drive 90 miles today. Much warmer, 54 degrees. My PINGING CAME BACK!!!! Come home, check coolant...it's back down to the fins again!!! Reservoir not any lower.

Pull plugs...left bank all good. Right bank BAD...heavy, crusty deposits (on one deposits were white, on another the deposits were black like tar) on each side of each plug, and 2 of the insulators on that side are white as white can be...like they've been steamed cleaned with coolant?

I didn't do a compression/cooling system pressure test. Couldn't this be either the intake manifold gasket OR head/head gasket? 4.0 OHV

 

[corkey]

probably a head gasket , it will leak into the cylinder , and cause the plugs to look like that

 

[35Remmy]

Yeah, coolant is going somewhere and it's not leaking it...it's not showing up in the oil, either. Isn't there a test they do that determines whether or not gases are getting into your coolant? BUT...this appears that it's an external gasket leak, not an internal, so I don't know if that would work.

Also weird that the radiator got that low and didn't suck any coolant from the reservoir, unless pressure on the cooling system is too low to maintain enough pressure to do this?

Would a lower intake manifold gasket push coolant into the cylinders if it were leaking?

 

[Cobraguy]

Not sure how you feel this is an external gasket leak with coolant in the cylinders like that. Intake gasket failure is highly unlikely. That would more likely put coolant in the oil. This is likely either a head gasket or cracked head/block. Hopefully...and likely...the former. You can do a leak down test and check it that way. You can have someone use an exhaust gas analyzer and see if they get a reading in your radiator. You can do a compression check. But it sure sounds like the heads are coming off...

Look at the inside of your oil cap and see if you can see any moisture or "milkshake" starting to form there.

 

[35Remmy]

Cobra...yeah, it's going to the shop as soon as I get back from vacation. I plan on pulling at least the head on the bad side.

Not really a big job, the OHV is pretty darn easy to work on, so I'm not too worried about it.

No, no trace of coolant is anywhere...oil, oil cap, leaks, etc.

 

[4x4xbrian.com]

pay close attention when you pull the intake I recall the coolant crossover is close to the intake runner on one end, and I've had these leak. however if its the middle cyl. no chance

 

[35Remmy]

Cobra...I've been thinking that my symptoms could be caused by a couple different problems...like if a couple injectors were spraying lean, I'd get pinging which could cause the head gasket the blow. If the water pump was shot and started to work and then not work (like cavitating), coolant would flow and then not flow causing hot spots causing pinging and then damage to the head gaskets/heads.

How DO they check the efficiency of the injectors without removing them from the vehicle?

I think when/if I remove the head on that bad side I'll replace the injectors for insurance sake. What do you think? What would be your plan of action if this were your vehicle?

 

[35Remmy]

4X4...thanks...I'll make certain that I look at this when the lower intake gasket is removed.

 

[Cobraguy]

I suspect your pinging is from over heating. You don't get it until you have coolant problems. Testing injectors is more of a guessing game than anything else if you are testing on the car. About all you can really do is do a cylinder balance test and see if you have any cylinders out of whack. But that doesn't limit it to injectors...that could be anything in the combustion process such as compression, ignition, etc. There are some tools out there where you can pressurize the rail then pulse the injector manually. Then you measure the pressure drop for each cylinder. I haven't seen one in a while...and they don't give you a complete assessment anyway. They don't let you see what the pattern is like for example...which is important.

If this were mine, I would do a leak down test and see where my leak is. The problem with a job like this on a high mileage engine is...where do you stop? I get the heads off and decide it needs rings. Then bearings of course...and if you are in that far, it might as well be bored and new pistons too. See what I mean? Next thing you know, you have a new engine! But if you think the short block is good...and the heads have to come off...I would order up a new set of heads for it. If it's got a lot of miles, it could use them. Shoot...the heads could be cracked too. I wouldn't rebuild your old ones as you can buy new ones cheaper. Go price a valve job, valves, surfacing, mag check, etc. I see new heads in the $250 range each. Heck of a price if they are any good.

But if you are lucky and it's nothing more than an intake gasket (which would really surprise me), then just fix that and leave the rest until you are ready for some major freshening.

New injectors after 100K never hurt anyone. You may not need them, but I can promise you that new ones will be better than ones with that many miles. I put new ones in my 5.0 when I rebuilt it at 100K...even though the old ones didn't seem to have a problem. But my 4.0 has 170K and is still doing well on the factory ones. I just run a can of 44K through it every few months. But I can promise you that the first time it needs to come apart, it will get new injectors.