I have tried searching around but I wasn't able to find anybody having all the same symptoms I've been having. So lately I have been experiencing some weird overheating symptoms in my jeep. Its a 98 4.0L with 138k, opening cooling system with a cap on the radiator. Whats been happening is its been running at about 220 or a little over and staying there. Just yesterday I topped off my coolant level before driving 3 hours home from Vermont, the first hour and a half or so the Jeep ran at a normal temp, but the rest of the trip it ran at 220. Sometimes the temp gauge will go all the way up to 250 or 260 for anywhere from a minute to ten minutes while driving, then it goes back down to 220. Now I know I have a coolant leak at the head gasket, but it is very slow, and it does not match the amount of coolant I have been loosing. I have been topping off my coolant every week almost, and it's not like I am leaving air pockets because I am burping it fully when I am filling it. So could a blown head gasket cause a leak into the oil pan or can only a cracked cylinder head cause that. I haven't checked my oil yet to see if it is milky, but Im not sure how else I could be loosing coolant that quickly.

One other thing that has been happening is when I start my Jeep up, whether its hot or cold, the electric fan has been coming on for a few seconds then it shuts off.

I have already replaced the fan clutch because I knew mine was definitely bad, but what I was thinking was get a new hi-flow water pump, along with a new thermostat, and a new head gasket. If I do in fact have a cracked head, I will replace that too, but I need some input before I start throwing money at it.

Thanks all!

 

'98 is self burping so that is not a problem to start with.

Curious why you haven't checked for coolant in the oil since that would only take a few moments?

 

Have you pressure checked cooling system yet including the cap ?

 

How do I pressure test it? Cap is brand new

 

How did you know you had a coolant leak at the head gasket?
Your loosing coolant, your temps are instable.
Time to start get down to business and start fixing what you know is already wrong.
Leaving cooling issues is gonna bite you if you leave them...

 

Havent had time to get more oil for when I drain the old, or can I check from the dip stick?

 

One other thing is the heat doesnt work, I'm pretty sure the heater core is clogged and I wasnt sure if that had anything to do with it because I have read the engine runs cooler when the heat is on full blast

 

Ive put a piece of cardboard under the engine while it was parked overnight and there was coolant stains on it

 

And what makes you conclude that leak is the headgasket!?

 

Just from visual inspection, I've checked other places that it could leak at and didn't find anything, so it's just my best guess, and because of how fast I am loosing coolant

 

Go to autozone and rent it should look similar to this...Pay cash when renting that way when you return it you get money back then instead of crediting you bank card . Tools are free to rent then attach to radiator and pump to 13lbs see where leaks at. Theres a adapter for cap in kit do same.

 

Or have it done, if not able to rent a kit.

Yes, coolant droplets on the dipstick. or check under your oil filler cap for crud....and under the radiator cap


Your heater core is like a mini radiator. When your temps are going into the red, turning the heater on full heat and the blower on high adds some to cooling the coolant...but by no means a permanent fix..

Like freegdr stated, having your system tested will give you an idea of size ...and location of the leak.

 

Yeah okay I will do a pressure test then. I checked all those and heres what I got, not sure about dipstick, looks okay to me, definitely crud under the oil cap and rad cap as well as around the rad cap too

 

Well, the bad news: that is oil in your coolant, judging by the brown creamy crud.
I guess you know what this means?

 

new head? or can a blown head gasket cause the same?