Yet another cooling system thread

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kmitch

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OK, let's start with what happened, what I've done, and where I am now. And I have been reading through the threads, but I wanted peoples advice before I tear everything apart and start replacing parts.

OK, so 2 weeks ago, water pump was making noise, I made an appointment to get it looked at/fixed. Further investigation showed the pump pully could be moved about a 1/16th inch on the top. Obviously a bad bearing, so I expected the water pump needed replaced.

Needed to get into work the next day, and when I got home the coolant was overflowing. Didn't drive it again except to get to the shop.

Shop replaced the water pump, thermostat housing (they said it was warped,) and the thermostat. Two of the bolts broke, so they had to extract those and replace.

Drove it the next day to the store and gas station and it was fine. Local trips, less then 10 minutes each.

Drove it the day after to work, 30 minute drive, 70-75MPH, and it started getting hot 1/2 way there. Got up to about 3/4 mark by the time I got to work. Coolant was boiling and overflowing. Had to put coolant in at lunch. Noted that lower radiator hose was cold to touch, top hose was hot to touch.

Drove home on side roads back home, between 45-50MPH, and it was fine.

Took to shop next day. They come back and say they think the radiator is clogged.

So, took it to church on Sunday, local trip, 10 minutes, did fine, no overheating or boiling.

Yesterday, I noticed the coolant was to the top of the expansion tank, drained some coolant. Warmed it up, made sure no bubbles were coming out of the coolant bleed screw thing on top of engine. (NOTE: that thing was on there tight like it had never been moved.) Took it on test drive. 45-55MPH gets to normal temp and stays there. Get on highway 70-75MPH and it starts going over that.

Today, drove into work, 45-55MPH normal temp. Get on highway going 70-75MPH it stays at normal temp for the 15-20 minutes I'm on highway.

At lunch, test drive down one exit on highway about 7 miles one way. 70-75MPH stays at normal temp. Turn around and come back, 80-85MPH it starts heating up.

So, I know the fan is working, that was kicked on yesterday after my test drive on highway. Coolant is all new HOAT. New water pump, and thermostat (brands unknown.) When the temp range goes above normal (1/2 way point,) I can cool it down by putting the heat on full blast. It will go back down to normal and stay that way.

At this point, if it's driving okay at 70-75MPH for my commute I'm willing to wait and see if it's just air needing to bleed out. I'll keep an eye on the cold level in the pressure tank.

So, from reading on here and elsewhere some possible things wrong.

1 - Could still have air trapped in system, could take several days, engine cycles to clear.

2 - Need to check the thermostat is installed correctly, and that it's not defective. Possibly replace with MOPAR unit.

3 - Need to check if radiator is clogged. I figure on doing that when I check the thermostat. I assume taking a garden hose, sticking it in the top hole, and watch the flow of water from the bottom is a sufficient test?

Thanks in advance.
 

turblediesel

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I had a Subaru that came with a 60% patched (plugged) radiator and it only overheated in stop-and-go traffic. Fine at cruise speed.

Bad new thermostat or warped head/leaky head gasket seem most likely to me.
 

sleazy rider

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If it wasn't overheating prior to the water pump change and the lower hose was cool, I'd venture its air in the system. Since it's pushing coolant into the overflow tank, I'd almost put money on it.

For giggles, I'd definitely check the thermostat for right side up.
 

eradicator006

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Sounds like air in the system and/or a bad thermostat. What I would do is drain the cooling system then replace the thermostat with a mopar then refill the cooling system through that bleeder hole. When I overhauled my cooling system the only way I could get all the air out was to fill through that bleeder port. Once coolant starts to come out of the port, put the plug back in and then top up the reservoir.
 

LibertyTC

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Cold in the AM..check Hoat or Zerex G-05 coolant to be at the cold line.
Was a Mopar thermostat installed or an aftermarket ???
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JeepJeepster

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What vehicle and year do you have?

Strange coincidences do happen, but Ive never liked using a stat that isnt OEM. Yet to have an issue with a mopar thermostat.

Depending on what vehicle youre working on, the bleed screw isnt critical on the Jeep liberty if the radiator cap is on the overflow bottle. I still recommend removing it and filling till its coming out of the bleed screw. If the Jeep is overheating and the lower hose is cold, its either a bad thermostat or a clogged radiator.
 
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HoosierJeeper

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Sounds like a radiator issue if the T stat is of good quality and is in the right way. Proper coolant level should be to the middle of the tank, not to the top.
 

kmitch

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Sorry, yes, 2006 Liberty, 3.7l

Drained coolant from radiator, so the coolant level is correct now.

Do not know the manufacturer of the thermostat. I'm just going to order a MOPAR one, plus the pressure tank cap so I can replace if need be. If I'm going to break the system open, would rather have a spare MOPAR one then wait for the part to arrive.

As far as the radiator, is using a garden hose and watching the flow through it sufficient to test?

Thanks everyone.
 

JeepJeepster

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Wonder if they did put the thermostat in backwards? It is an odd design, having the stat in the lower hose, maybe they put it in backwards if they haven't seen that setup before. That would certainly explain why it suddenly started overheating after they had it.

Im not an expert on radiators, not sure how/why they fail other than someone packing them full of leak stop, but I would think if it easily passes a water hose at full flow it should at least allow enough flow to let the lower hose get warm if the Jeep is overheating.

FYI, the 3.7 likes to self destruct when it overheats.
 
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LibertyTC

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kmitch please familiarize yourself with the cooling system, Section 7 Cooling.
Here is the factory manual : http://www.colorado4wheel.com/manuals/Jeep/KJ/2006-KJ-SM.pdf
Here is the correct orientation of the Mopar thermostat.
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Start by draining the system, bottom of rad petcock, & inspect to see if it has the mopar thermostat.
Only use Hoat or zerex G-05 coolant.
If the wrong coolant has ever been used in a KJ before, the whole system has to be flushed big time.
 

daves06lrenegade

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daves06lrenegade

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Big Al

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If the wrong coolant has ever been used in a KJ before, the whole system has to be flushed big time.
Has anyone done this big time flush before.
Kind of thinking a few bottles of simple green and a few fill ups completely to remove the degreaser.
Run it around the block for 30 minutes minutes.
How about the prestone flushing fluid. Not sure if it is compatible with the HOAT fluid.
 

LibertyTC

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The best big time flush comes from utilizing the dealer's coolant re-circulating machine. Out with all the old including the block & in with new Mopar Hoat completely.
Destination Jeep on the North Shore has machine & sometimes they may have spring flush deals. Call around for quotes.
As the Mopar water pumps have a plastic impeller, I'd be also concerned about adding chemical treatments. Ph balance is also important.
What you may choose to do is your choice, but if I was doing my own flush, it would be a distilled water flush only & then full drain.
Drop lower rad hose, new hose & new mopar thermostat & add the Hoat.
Then use a coolant tester to know what the cold rating is.
 

kmitch

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OK, so I'm tackling the coolant system today.

Got Murray radiator from O'Reilly Auto Parts. I've installed these in other vehicles and am confident enough in their quality. Should have went ahead and gotten new hoses and clamps.

So, I got the old radiator out and I do believe that it was clogged. Looks like previous owner (or worse the car lot I bought it from) used the stuff to seal a coolant or head gasket leak. Any other ideas on what this gunk is? Mixing coolant types?

Joy of Joys. I'm assuming I should just replace the coolant instead of using what was drained.

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Second issue, the auto repair place DID NOT replace the thermostat correctly. My finger is on the top bolt of the thermostat housing and as you can see the air bleeder is clocked way wrong. Looks like a motorad thermostat. I will be going back to the repair place and let them know the error of their ways. (Won't be getting anything other than tires from them in the future either.)

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I'll be posting a follow up once I get everything taken care of and it's back on the road.

I guess I should just plan on doing a head gasket change, along with getting the heads looked after.

Shout out to everyone on here willing to give input.
 
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tommudd

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If you have that in the radiator, then I can just imagine what the heater core looks like inside

and yes does not seem like your shop knew what they were doing.
I would not even trust them to install tires anymore
 

kmitch

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If you have that in the radiator, then I can just imagine what the heater core looks like inside

and yes does not seem like your shop knew what they were doing.
I would not even trust them to install tires anymore

Heat inside the car seems to be hot and steady. I really hope I don't have to replace that.

Will only use them for any warranty repairs on the tires, otherwise, yeah, they burnt a good customer because they didn't take the time to know what they were doing.
 

kmitch

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Road test indicates a complete success.

Did my commute route, 29 miles one way, 80-85mph (faster than normal but I wanted to push it a bit.)

Temp gauge stayed straight up the whole way there, stopped by mcD’s and got a soda, no boiling. Turned around and made the trip back with no issues.

will keep an eye on the coolant level but I think this problem is resolved. Now I can move on to the brakes.

Love it when a plan comes together.

Thanks again everyone.
 

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