Smaay

ok driving home yesterday my needle tipped into the red. i was climbing a hill and had to kick it into 3rd just to make it up. it cooled down on the downhill side but stayed hot the entire drive home.

when I got home it was puking coolant out the overflow. and i could hear it boiling.

today i did a compression test. 135 across the board. that sounds low to me. I also did a coolant flush.

I checked my timing for the hell of it and it was a 5 degrees, the dizzy was fully retarded to i advanced it to about 12 and also installed new NGK sparkplugs.

well to make a short story long, after adding in new coolant and driving around the block, i felt a slight increase in pep, the engine stayed normal, oh I also changed the oil and the pressure seemed a little higher.

when I got home and shut off the engine, I could still hear coolant boiling in the block. That does not seem normal to me.

rworegon

Several things come to mind:
1) Radiator is dirty on the exterior or plugged on the interior.
2) Radiator cap is not sealing and working properly.
3) Fan clutch is not engaging when needed.
4) Coolant level was low initially.

Are you sure you are not hearing cooling boiling/gurgling in the radiator or the coolant overflow tank?

RJR

Lancaster is about 4000' elevation, I believe. 135 psi compression is normal for that altitude.

Smaay

1) flow is pretty good, it is rusty looking inside and one of the tabs is broken away from the mount. I will be replacing it soon.

2) quite possible, the one I have is looking ragged

3) fan is working properly, I let it idle and it got warm, the fan kicked on and it brought the temp right down

4) it was low after is was all puking out. not sure how it was before.


im not quite that high. only about 2500. Palmdale is closer to 3000.

Smaay

well I replaced the radiator cap, thought all was well, but I overheated again, im loosing coolant somewhere. it ran hot, i pulled over and popped off the radiator cap. I added 3 bottles of water (single serving water bottle) after that I was able to drive home with no issues.

So it seems like im loosing coolant somewhere, and after enough is gone, i overheat.

I did a compression test and it was 135 across the board. I dont think i have a blown head gasket, but i cant rule anything else out.

rworegon

Pressure test the cooling system and it just may show where the coolant is leaking. Use a mechanics mirror and a good light and look everywhere on the engine for the tell-tale coolant crust. Give the plastic overflow tank and all coolant hoses a good looking over too.
There is a U shaped coolant hose at the back of the block that is known to leak.

Smaay

yep I did that, luckily I have no leaks from hoses or the block anywhere. At the temps Im seeing im sure I would have a gusher if I had a leak anywhere.

rworegon

Are you getting the white smoke out the tail pipe? How does the oil and coolant look? Any coolant in the cylinders after pulling the plugs?

Your local auto parts store may have a product called Block-Chek which will help in the diagnosis.

Smaay

no signs of coolant in the oil and no smoke out the tail pipe

dromomaniac

Got to be the Waterpump, right?

Not sure what else it could be. Since you're getting super-heated coolant puking through the overflow you must be getting flow through the thermostat and the rest of the system. Everything else sounds in order, including the head gasket. Since water pump is completely dead, your coolant isn't returning to the radiatior and cooling. Instead it cooks in the block until expanding through the overflow.

Edit: I guess that it's conceivable that the radiator or outflow hose are blocked, but my vote is still waterpump...also edited to clean-up bad (well, the worse, at least) grammar.

Smaay

so i bought a new radiator and fan clutch from rock auto. Of course the core was damaged in shipment. I sent it back yesterday. should get a new one in a few days

dromomaniac

Does this mean that you identified a problem with your radiator? I just reread the thread and don't see that. Was there a crack?

I just went through months of screwing with a XJ cooling system with more leaks than components but somehow I'm still curious about the subject.

For what it's worth, I put a mid-range CSF radiator in my truck a few years back. Works great. I've spent months driving back and forth in rush hour traffic and temps up to 122. The gauge never goes over the halfway point.

MaK92-4RnR

How do you know its running hot? Do you have a water temperature sensor installed?

Kiroshu

X2 on a flow problem.

Verify temperature of the upper and lower radiator hoses.

Blockage..?

Thermostat..?

Water/coolant pump..?

Just_ Rollin'

The oil cooler fills with rust/crust if you have one. Not critical but adds to the decreased flow of coolant in that area. All you need to do is blast it out with a hose and water.