4.0 cooling issues (head gasket???!?!?!)

Folks please don't curse me for asking a question about my WJ in this forum.. I have not had any luck in other forums.. But here is the deal.. wj overheats to redline... fan working properly, new t-stat recent water pump (2 yrs old) ONLY DOES IT ON HIGHWAY. Figured it was a collapsing hose .. LOWER hose you would think... but no its the UPPER HOSE.. so I replaced the hose and the radiator cap for good measure, when the engine runs at RPM with load, the upper radiator hose collapses and the engine temp instantly goes to red line... Is this a sign of a head gasket blown or a head crack (its a 2000) There is no milkyness in the oil so I dont think oil is getting into the cylinder walls but could i still have a blown head gasket? What would make my radiator hose collapse? an obstruction? should I replace the radiator? any thoughts.. I have pretty well blead the system like I would on my XJ so I don't think its air in the system

I had the same problem in both of my xj's i have owned here is what i did. I went with a heat buster extreme 3 core radiator, and a heavy duty tranny cooler. Since on the xj's (notsure bout the wj's) the tranny and coolant run through the same radiator and the stock ones are only one core. That is what i did. I am running a 6 1/2 inch lift and 33's. I can tow my camper or run 4 low on the trail all day and the jeep WILL NOT go above 160 degrees. I also put on a new fan shroud since mine was cracked and hard wired in the electric fan so i can flip it on when needed. Just an idea? Good luck

white smoke out of the exhaust?

btw I like your avatar haha

fan on backward?

air in cooling system?

do you have to keep adding coolant?

I had a similar overheating problem. Both hoses were collapsing. Turned out that the overflow hose was clogged. Blew it out with compressed air and all is good.

I just got my jeep back today from rad shop..It would over heat when i drove it for awhile, flat, up hill, down hill, didn't matter... Had the rad rodded out and the block flushed... Drove it tonite, it was 100 outside... Took it on a 3 mile grade uphill of course.. Temp got to 195.. I have a 185 t-stat in it... When was the last time you had your rad looked at?

Well.. I think it may be a clog...

xjohnnyc ... your talking the hose from the puke bottle to the radiator cap right?
i blew threw that one yesterday and it was clear....

Im just curious if it is in the radiator or somewhere else in the system... Is there a way to check radiator flow???

I am going to do a leakdown test on the radiator (this should show if it is the head gasket right??)

wilcharl said:

xjohnnyc ... your talking the hose from the puke bottle to the radiator cap right?
i blew threw that one yesterday and it was clear....

Click to expand...

Yes.

I guess I was lucky that my problem turned out to be something so stupid.

You know that most tstats get stuck CLOSED after a serious overheating event, right?

A blown head gasket would not IMO cause your radiator hose to collapse. You are barking up the wrong tree I think. That said you will flunk a leakdown test if the gasket is blown.

A collapsing radiator hose is either the cause or major symptom of your problem. I doubt it's the cause though. Collapsing hoses are rare today, they are supposed to be self supporting. I asked the guys at NAPA for a spring to put inside my lower hose and they said they don't even carry them anymore, too many people were leaving them in there forever and then chunks of rusty wire were getting stuck in their coolings systems.

I guess I'll go X2 on an obstruction. I would pull the whole system apart and inspect thoroughly. Remove and test your tstat in hot (not boiling) water and check it with a thermometer to make sure it starts to open at it's rated temp. Test the engine with the tstate removed, in fact just leave the tstat out until you solve the problem. Then you MUST re-install a tstat of the CORRECT temp or welcome to permanent open-loop mode because the engine can't warm up. I suggest a fail-safe tstat, they're designed to stick OPEN instead of CLOSED after an overheat.

I should add that the most common reason for those closed systems overheating is that they can't hold pressure. Although again, that doesn't jive with your collapsing hose. But I would suggest converting to an open system at some point.

does that only have the electric fan? some fan relays fail and the fan wont work at all. are you adding coolant. some of the 2000/2001 cylinder heads were prone to cracking between cylinder 3 and 4 rocker towers. a slight coolant trail may be seen if you remove the oil cap.