Jump to content

Overheating Diagnosis [1989 Jeep Comanche 4.0L I6]


Recommended Posts

  • Replies 51
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Posted Images

12 minutes ago, james-mc said:

New tstat and coolant cap is supposed to be here tomorrow. Figured Id start with the cheapest solutions lol

 

Which coolant cap did you order? The Volvo style is a must, OE style will expand with the filler neck and release pressure. That cured my overheating issues for a good while until other problems came up. Stant 10244 <$10 on Amazon or parts stores

Link to comment
Share on other sites

Well the day I was going to work on the jeep it snowed here lol. Also my parts didnt arrive until yesterday. Id hoping its going to be warm enough tomorrow to flush the system a few times. The truck is sitting at my dads house so i havent been able to check for any hoses collapsing.

 

This is the cap: https://www.napaonline.com/en/p/NDP81950501

 

Also my tstat housing has a plug that can be removed with a large allen wrench. Dumb question but what is this plug for? Could I burp the system by removing the plug?

Link to comment
Share on other sites

On 4/19/2021 at 12:19 PM, MiNi Beast said:

Cheapest be figuring out the issue before buying anything. good luck. :doh:

Haha true but its only $10 for tstat, gasket, and cap. And if its something else like a weak hose collapsing I can always return the parts I suppose lol.

Link to comment
Share on other sites

1 minute ago, james-mc said:

Haha true but its only $10 for tstat, gasket, and cap. And if its something else like a weak hose collapsing I can always return the parts I suppose lol.

no you put on shelf it will be used, not a waste of money when maintenance parts. :L: 

Link to comment
Share on other sites

Ok i got an update: 

New Reservoir cap seemed to fix the coolant dumping issue. I pulled the tstat to test later and just installed the new one. 

I will be flushing the coolant system this weekend as it is pretty rusty.

 

I let it idle until about 200 range. I didnt take it for a drive.

No hoses collapsed. Lower hose didnt feel as stiff as new but didnt collapse. Upper hose will need replaced as it looks like the hose clamp has cut into the hose on the bottom.

 

So after the temp was high enough for the tstat to open I gave the hose a good squeeze and it didnt feel like there was much pressure behind it. 

 

Also while it was running I backed out the plug on the tstat housing and it seemed like water was barely flowing out. I expected it to spray from the water pump circulating and it was just line weak pulses. 

 

Could also be the water pump. I'm not sure. My dad said check with the yall before I buy water pump lol

 

 

20210422_171814.jpg

20210422_181731.jpg

20210422_181735.jpg

Link to comment
Share on other sites

Also added more antifreeze to between max and min level. Then i added even more antifreeze with the engine running until it quit sucking my reservoir dry. Installed cap back on and let idle for a bit. Then I cracked the cap until pressure leaked out and more coolant filled the reservoir to the max line.

After that no more binging and purging of coolant from/into the reservoir. After shutting the engine off the coolant settles to the halfway mark where I originally filled it. I'm going to write that issue off as a bad cap not holding pressure.

Link to comment
Share on other sites

1 minute ago, zomeizter said:

I fought an overheating issue with a SBC before where there was insufficient coolant circulation, turned out to be the impeller in the water pump had become loose on the shaft. This drove me crazy for a good minute...

Its funny you mention that because I noticed my pump had kind of a wobble to it and i was thinking maybe it backed enough to not spin the impeller

Link to comment
Share on other sites

If you still struggle to resolve the issue, just pull the water pump and inspect it.  Too much air in the system can lead to weak pumping action, but I've also seen my share of failed pumps.  Water pumps are generally considered wearable items, so it's quite possible you're due for a new one.  But don't throw a new one at it without checking!

Link to comment
Share on other sites

5 minutes ago, scaleless said:

If you still struggle to resolve the issue, just pull the water pump and inspect it.  Too much air in the system can lead to weak pumping action, but I've also seen my share of failed pumps.  Water pumps are generally considered wearable items, so it's quite possible you're due for a new one.  But don't throw a new one at it without checking!

This one has a few years on it from what i understand. Oreillys has the new pump in stock. I guess i could pull it and inspect it then if its bad run and get the new one.

 

I'm going to do the flush this weekend. Ill have to run some tests on the pump. Could I loosen the serp belt and spin the water pump while that tstat plug is out to see if fluid pumps out of the plug hole?

Link to comment
Share on other sites

upper hose be still when running as water is being pumped through. squeeze in hand should bounce right back and thinning of walls with older hoses can be seen with inspections. lower hose should also have a spring in it to help in the anti-collapsing . sounds like you may have a weak pump, and if its new to you, as you haven't did this already, then id would just plan to replace pump just for good measure. not to say drive it a bit and see if it wasnt just that cap and some air. water is flowing either way. but does it maintain temp...

Link to comment
Share on other sites

35 minutes ago, MiNi Beast said:

upper hose be still when running as water is being pumped through. squeeze in hand should bounce right back and thinning of walls with older hoses can be seen with inspections. lower hose should also have a spring in it to help in the anti-collapsing . sounds like you may have a weak pump, and if its new to you, as you haven't did this already, then id would just plan to replace pump just for good measure. not to say drive it a bit and see if it wasnt just that cap and some air. water is flowing either way. but does it maintain temp...

Ok. Its like a $40 part from what ive seen. The hose seemed like it was pretty stiff with the tstat open but I just couldnt feel a good flow like I have on other vehicles.

 

I didnt get take it for a drive since it was getting late. But I can say once the engine hit 190 and the tstat opened the engine did cool down to around 165-175 (according to the temp guage). After letting it idle for about half an hour the guage sat around 200.

 

 

I will take it for a drive this weekend. If it doesnt overheat I might put in some of that coolant system cleaner in her and drive a little bit before the flush.

Link to comment
Share on other sites

yeah not bad. these parts are just stupid simple upgrades for these jeeps. :scholar: jeep go no where if it ain't running right. maintenence parts easy buy decision, peace of mind with reliability. She don't need to be pretty if she gets you home. :comanche:what do you do with that stimulus check???? Buy jeep parts to keep it running down the road. #Curbs be rough in #MaynardHood..

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share


×
×
  • Create New...