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Overheating/ head gasket?

784 views 9 replies 3 participants last post by  glazierlaird 
#1 ·
Ive put in 3 rads in my 2004 Grand Cherokee Limited The first after I bought it and my mechanic said the rad had lots of crap in it. First flushed it then changed the rad. The end of the rad blew apart after about 3 weeks. Mechanic said must be faulty rad. Rad 2also blew after abou 1 month. Mechanic said must be head gasket causing air build up. I had the head machined and replaced the head gasket,electric fan and rad. 13 months later the bottom rad hose blows off the rad, replace clamp, refill rad. Today the top rad hose blows off on the highway. Different mechanic does compression test, 70 in #1 cylinder over 200 in all others, no difference wet or dry test. Is this a head gasket again?? What would cause thhis to happen?:cheers2:
 
#2 ·
How many rad caps have you changed? T-stats?

200PSI!!! Should be ~100-140 more or less depending upon wear. All cylinders being close to each other is important also.

One cylinder low could be rings or any other problem such as bad head gasket, cracked head, cracked block.
 
#3 ·
Overheating/ head gasket

3 new rad caps one with every rad, 1 new thermostat. This is over maybe
one and a half years. 200 is too high? I wonder about the accuracy of the mech compression tester. He did say he had to change spark plug and coil in #1 as it had a bad misfire before doing the test. I realy dont understand the rad hose blowing off.
 
#4 ·
Fill out your profile so everyone knows what you are running.

4.0 water pump OEM # 05012366AC

4.7 water pump OEM # 53021187AA

If the T-stat is getting put in the right orientation then keep in mind that there are reverse flow water pumps for some jeeps. A standard flow water pump travel in the same direction as the harmonic balancer. Om reverse flow water pump does not.

http://www.flowkoolerwaterpumps.com/info/standard_reverse_rotation.html

Often overlooked is the bottom rad hose. Some can lose their strength OR come with an internal spring that reinforces them and is removed. If the hose is soft or loses its inner strength it will collapse when you get the engine rpm's up preventing the coolant to travel through the cooling system.

Have you monitored your temperature gauge after it was fixed all those times?
 
#5 ·
overheating /head gasket

I added to my profile but can't seem to upload photos. The engine is a 4.0 everything is stock. The only model number I can find is Special Edition written on both sides beside Grand Cherokee. Had it towed to a different shop today where the last head gasket was installed. They will retest the compression tommorow. I was told yesterday it could be a clogged heater core???
 
#6 ·
I added to my profile but can't seem to upload photos. The engine is a 4.0 everything is stock. The only model number I can find is Special Edition written on both sides beside Grand Cherokee. Had it towed to a different shop today where the last head gasket was installed. They will retest the compression tommorow. I was told yesterday it could be a clogged heater core???
A clogged heater core prevents heat from being made for your comfort but DOES NOT cause radiators to blow up. ANYONE who tells you that is an idiot.

You do not have enough posts to upload photos yet. Photos aren't that important at this point for this problem.

Why do I think the idiots working on your cooling system do not know how to purge your cooling system of air.

What does your temp gauge do before this Jeep blows a radiator? Or do you only pay attention to the radio? Really if this engine is overheating didn't you ever notice the temp gauge spiking?
 
#7 ·
overheating/head gasket

Actually I do watch my gauges. The temp does not spike until it's too late. The jeep had lost power this week I immediately checked the temp and it was normal. I pulled to the shoulder and slowed and watched the temp it stayed normal then straight to red warning light. On the road you could see the trail of antifreeze so the hose blew before the heat went up. I have read other posts about air locks in the rad but have not seen anything on rads that blew or hoses blown off because of it. Because of the problems I have had in the past I check the fluid levels weekly. For the last 10-12 months it has stayed at the correct level with no need to add. I don't see how an airlock could develop after that amount of time without something like a head gasket leaking.
 
#8 ·
Actually I do watch my gauges. The temp does not spike until it's too late. The jeep had lost power this week I immediately checked the temp and it was normal. I pulled to the shoulder and slowed and watched the temp it stayed normal then straight to red warning light. On the road you could see the trail of antifreeze so the hose blew before the heat went up. I have read other posts about air locks in the rad but have not seen anything on rads that blew or hoses blown off because of it. Because of the problems I have had in the past I check the fluid levels weekly. For the last 10-12 months it has stayed at the correct level with no need to add. I don't see how an airlock could develop after that amount of time without something like a head gasket leaking.
If it ran for some time it must have finally purged any air in the system if any existed. If the coolant levels never changed in the overflow tank then we might assume that the cooling system was filled/purged properly.

That is ran well for some time then just blew a rad hose...was it always the upper hose? And you have blown up a few radiators also.

This indicates to me that the cooling system is building up way too much pressure. What pressure range is the rad cap? Caps are rated for sea level pressure. IIRC the rating for your engine would be 12 - 15 lbs but I would verify that on your own.

Do you live at a higher altitude? At a higher altitude you need a higher pressure cap to compensate for the elevation.

The pressure raises the boiling point of water. That is why when you remove the cap the damn radiator 'geysers' on you.

At higher altitudes you need more pressure but that poses a stress problem also doesn't it.
 
#9 ·
If cyl #1 really is lower than the others, then do a leakdown test on cyl #1 to determine where the leakage is.

You really need to learn to do the work yourself or find a good mechanic who you trust. And don't be afraid to get a 2nd opinion before doing something like a head gasket.

+1 on the advice to replace your radiator cap
 
#10 ·
Unfortunatly I don't have the time at this point to do the work myself. I deal with a licenced mechanic I have known for 30 years. That being said does he do everything right????? He believes it might be the head gasket again but more likely a cracked block or head. Replacement engine delivered today. His opinion air being forced into the cooling system through a crack/ head gasket creating pressure in the cooling system and blowing rad hose off/ rads in past. When I had the head redone the problem stopped for about a year then started again. Did he do a bad job on the head? He said the oil was full of antifreeze. When it blew last week I was not only late for work but had about 20 people waiting for me to open the door so I had little time to check out the engine. Its unfortunate I dont have the time or the tools and knowledge to do jobs like this but this is the first jeep I have had that has problems like this.
 
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