Jeep troubles

[Tsalagi]

My Jeep Cherokee blew a head gasket last week. Real fun where we were, too.  It spent a week in the shop, and guess what happened when I drove it home tonight? It redlined and boiled over. Looks like it'll be a while before I can get out to shoot bow, collect pinyon sap, or what-not because I want it gone over with a microscopic-toothed comb this time. Not happy!!!  Oh, and it's snowing again. Charming.

[nugget]

Cherokees and any jeep product with a 4.0 6cyl are notorious for overheating. They are bad to get an air pocket in the engine when coolant is being put in.

[mullet]

 A lot of times someone will put the fluid in before the 195 thermostat opens up. I turn the heater on and let it run for a while, then check the water again.

[boo]

if you want to email me kellerknives@yahoo.com ill tell you how to bleed the air out of the system. I spent three months battling the same problem after my daughters jeep done the same thing. .

[sailordad]

the best to make sure all air is out of the system is to use a "radkit" to refill the cooling system

[Tsalagi]

Thanks for the info! I didn't know any of this. Odd thing, a few days before the head gasket blew, the heater quit working. I'd almost swear the two things are related somehow, but can't put my finger on it. The radiator was full of rust, which is strange as I just had the radiator and water pump replaced last year.

[sailordad]

tsalagi, you say the heater quit working.does that mean the fan or nor heat coming from it?
if it was no heat,that was probably caused by loss of coolant due to the head gasket leaking it.
when the coolant leaks out the system fills with air,its hard to keep air hot enough to use for the heater,you blow air across a heater core thats
full of air and it cools off almost instantaneously.them jeeps are known for bad heads/gaskets.not to mention intake/exhaust  manifolds that like to warp and
t-case out put shaft seals that like to leak and whel bearings and other things.
the rust comes from using straight water in the cooling system.it doesnt matter if you had the radiator adn coolant pumps replaced or not.water in the engine block doesnt take long to create rust.rust is a by product of heating water in a metal.heating water in metal actually causes rust faster tahn just leaving water sit in metal without heating it.i as a professional automotive technician would never ever recomend using straight water in an engine cooling system.always use a 50/50 mix of good   quality anti-freeze with water.never pour coolant in the radiator and then add water,always mix it prior to putting in the system,if its done the other way it may never mix properly.the rad kit that i mentioned before,is a device that hooks up to the fill neck on the radiator.then you attach an air hose to it and creat a "vacuum" in the cooling system.this vacuum will be great enough to collapse all radiator and heater hoses.this process removes any and all air (if done properly) from the cooling system.
once 26" of mercury have been achieved(vacuum) let it sit for atleast 1 mins.thie should pull any air that may be trapped in the system,if it does not hold this vacuum then there are leaks somewhere in the cooling system and that will ingest air back into the system.air in the system is bad and can actually cause a "hot pocket" of steam that can cause internal damage to the system.if the system is holding vacuum then its time to use the "rad kit" to fill the system.i have used this device and love it.
i do alot of cooling sysetm/ac work nad swear by this tool,as a matter of fact FORD does not recomend filling a modern cooling system any other way.

good luck

[Tsalagi]

Thanks for the great information, Sailordad. I appreciate it it a lot. The heater blows, but doesn't put out heat. And did that after the head gasket was replaced, too. Oddly enough, when it redlined, I turned on the heater full blast to try anything to vent the heat and the needle climbed away from red. Really weird. But it still vented from the escape port on the reserve coolant tank.

This jeep has me scared now. But the information you gave helps me a lot.

[sailordad]

the heads on them like to crack externaly
very carefully inspect fot a white residue or what looks like calcium build up around the edges of the head in areas
near the bolts for the intake/exhaust manifolds etc.

if it was doing that right after you had the head gasket replaced,then they didnt either fix it properly or get the air out of it.
them things are touchy to get all the air out,kinda like the old ford rangers were

good luck

[Tsalagi]

Thanks for the help, everyone. The jeep appears to be good to go now---cross fingers, knock wood, and everything.

[sailordad]

well mechanic minds want to know

so what was it?

[Justin Snyder]

Yes, what was it? Sounds like air bubbles to me. Most other problems take more time to manifest themselves if it was filled correctly.

Whenever I change head gaskets I take the heads in and had them milled and scoped. They are rarely flat if they have blown a head gasket, and milling makes them flat again. When they scope them they check for microscopic cracks in the head that will cause problems. It costs a little but saves a lot in the long run.

[Badger]

I have a crew of 10 mechanics working for me and trying to get all of  them to understand that the air has to be bled out before you release a car is like impossible. They always claimed they ran it long enough before putting the cap on and a customer will take off go about 2 miles and then overheat. Always happens to the same mechanics. I never though about evacuating the cooling system like an a/c system sounds like a good idea. I let them run until the thermostat is in the sty open position instead of the pulsating it goes into when warming up might take 30 min or longer. Steve

[HatchA]

If the heater stopped blowing hot air before the head blew, it sounds to me like the heater rad busted a tube/pipe (possibly from the water freezing, if you've got snow going on there), the coolant slowly leaked out and the head finally blew. 

I was gonna suggest the water pump but you said you got a new one along with a rad.  Rust in the rad probably came from residue from the chambers of the motor itself as it probably wasn't flushed out when the pump and rad were changed.

I second Sailordad's advice regarding frequent close inspection of the head.  Couple of things to be wary of...  Make sure whoever repaired it skimmed the head properly AND used a Jeep gasket as the difference between brand name and spurious gaskets can be as much as 50%  (as in: the spurious gasket is half as thin as the brand name make).  Also, check that the head bolts have been torqued correctly.  Personal experience showed me that not every mechanic knows how to use a torque-wrench properly 

Now I tend to do as much work on my own car myself.

Hope it all works out for you, man

Steve.

***EDIT***

I let them run until the thermostat is in the sty open position instead of the pulsating it goes into when warming up might take 30 min or longer. Steve

I carried out open stat surgery on a Subaru Legacy that kept overheating.  Removed the stat altogether and the overheating stopped.  Just meant the flow of water went the full way around from the get-go.  Engine is still perfect!

[Tsalagi]

Well, we replaced the head gasket and bolts and milled the head before that. The mechanic was trying to save my radiator, but said he was flushing tons of rust out of it. But it didn't work and it redlined the first few minutes out of the shop. So, he replaced the radiator and before that, flushed it again real good and did everything needed. He said all kinds of rust was coming out of it and it was the radiator just retaining all that crap that was the problem. So now it's running great. He did a few hours of work on it the second time he didn't bill me for and we worked out a trade for the radiator and labor, which helps me a lot.

The heater quit blowing hot air before this happened and it still won't blow hot air. So, I'm going to have him tackle that next. I'm going to keep a close eye on the coolant and radiator just in case I've got a leak from the heater rad. I'm going to check with the mechanic about that, too. He needs to swing by and pick up the thing I traded for the repair.

I think I got a bad deal from the mechanic that put in the previous radiator and water pump. It isn't the same mechanic.

Again, thanks for all the help. I feel a lot better about the repair knowing this.