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Overheating issues

Yeah - Im probably just going to go and have it reserfaced anyway. Get it cleaned up and checked for cracks. They had it up on craigs list because it was sitting in her father in laws backyard since december. their coolant bottle leaked and was over heating. Thats what they said the issue was. and yes i can see how that happened, But it wasnt just because of the leak like i had thought. They didnt even know what was up. So i cant blame them. I want to but... :)

Blue Devil is basically the same thing as that glass sealer but like i said I cant run it more then 5-10 min TOPS before there is to much presssure in the system. and as far as i know, it takes somewhere between 30 and 50 for any of those types of things to take effect. I would MUCH rather toss some in and call it good. But unless I can find a way to releave the pressure without losing alot, or any, coolant while its working, its not an option.
 
Ditched the Blue Devil since it wouldnt idle for more then 5-10 min before building up to much pressure in the coolant and literally blowing off the bottle cap...SO...

Got the head off.. 4 hours later heh. Those manafold bolts SUCK lol. Pulled it out and there is NO break in the head gasket... not one nor the did any of the cylinders look steam cleaned. There is however so much buildup in the coolant passageways that they were completely pluged.

Head and block look true. Took a strait edge to em. no gaps. no cracks that I can see.

Valves look great. all but one was a nice tan color. The front one is semi tan with some black in there from burning oil. I might replace the valve seals just to make sure its done right. I DO NOT want to do this twice lol

The water pump was shot and was leaking water. But i cant see anything that would account for the extreme pressure buildup.

Im going to take the head to the machine shop after this weekend and have it pressure tested.

The only things I can think of that would cause that pressure would be that it was pluged (it was bad) and it was the water pump that was building up the pressure. OR that is a crack in the block... but again no water was getting in the cylinder heads.

Thoughts?
 
No 92 was the start of the HO engines... RENIX is 87 to 91 - or at the very least there was some other change. But for the most part when im looking for parts for my 89, my range is 87 to 91.

Hope that helps.

Ed
 
Just a thought- Could it have been pushed too far by topping with tap water over and over? that and snakeoil bandaids- resulting in super clogged up? AND never properly burped!
-Might consider- when back together, Flush with chemicals several times then, afterward, change the waterpump and radiator,etc. and a GOOD burping. Just a thought.

Good Luck
o
 
Just another brainstorming idea. Some of the water pumps run backwards to the others. One of your posts said that the water flowed different than your other XJ. Make sure you get the correct new pump and compare it to the old one you took off. (but don't assume the old one was correct)
 
I have seen that kind of fast overheat once before on a 97, new rad, hoses, tstat, belt, cap and once the tstat opened out came a geyser from the open filler neck. Ended up being a 2 year old water pump, all the vanes were gone on the impeller, new pump fixed it.
 
GinisKratos said:
No 92 was the start of the HO engines... RENIX is 87 to 91 - or at the very least there was some other change. But for the most part when im looking for parts for my 89, my range is 87 to 91.

Hope that helps.

Ed
Click to expand...

Renix 87-90, HO OBDI 91-95, HO OBDII 96-01
 
Well, its back together and things seem like they are working well. I need to replace the coolant bottle cap, its not getting tight, tossed some plumers tape on it so its holding pressure but you cant get it tight, just pops and gets lose again. Gets just tight enough but not tight...

Had the head pressure checked and it failed on 2 valves, i had them replace the seal on those and once it passed the test, I had them resurface it. Got it home, replace the rest of the seals (cost me about a buck for each seal and for me to lap the valve myself vs the 19 each for htem to do it heh)

Tossed everything back on and i think im still going through the burping process. Although the tstat is opening on que now, my temp never goes past just over 100. Not even half way to 210. Was working fine after i got it all together and was cycling in the coolant and making sure the gaskets were on there well, no leaks, etc...

But on the test drive it wasnt going up. Pulled over every mile or so to make sure things were good... Heater is blowing heat, upper and lower rad hose are pressurized and are hot. Water in the bottle is hot as well. So im thinking its just something with the temp sending unit. But i have no idea lol was working fine then just stopped. Am I missing something? This is basically my first time doing the head. So i wanna make sure heh. Thanks!
 
A reported fix for the coolant bottle cap is to put a worm drive hose clamp around it to strengthen the grip on the threads. If your heater is blowing hot and your hoses feel hot, something has to be wrong with your gage or sending unit. If you have an ohmmeter, you can check the sending unit resistance.
 
GinisKratos said:
Well, its back together and things seem like they are working well. I need to replace the coolant bottle cap, its not getting tight, tossed some plumers tape on it so its holding pressure but you cant get it tight, just pops and gets lose again. Gets just tight enough but not tight...
Click to expand...

The hose clamp around it will certainly keep it from popping off.

Tossed everything back on and i think im still going through the burping process. Although the tstat is opening on que now, my temp never goes past just over 100. Not even half way to 210. Was working fine after i got it all together and was cycling in the coolant and making sure the gaskets were on there well, no leaks, etc...

But on the test drive it wasnt going up. Pulled over every mile or so to make sure things were good... Heater is blowing heat, upper and lower rad hose are pressurized and are hot. Water in the bottle is hot as well. So im thinking its just something with the temp sending unit. But i have no idea lol was working fine then just stopped. Am I missing something? This is basically my first time doing the head. So i wanna make sure heh. Thanks!
Click to expand...

Also feel around the elec fan switch in the radiator tank (be careful). It too should be pretty hot. If not, you still have air trapped inside.

Make sure the coolant temp sensor wire on the back of the head is connected snuggly.
 
My last two coolant bottles have both been Chinese, and they came with caps, and both caps would "pop" loose when I tried to tighten them down.

Went to dealership and $11 for a cap, tightened right down and no problems.

Never thought of trying a worm clamp, that's a pretty good trick.
 
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