james-mc Posted April 17, 2021 Share Posted April 17, 2021 Well after many of the various repairs on this ol jeep I've run into an overheating issue. When I first got the comanche it did have an overheating issue. Fairly new water pump and replacing the radiator seemed to fix it..or so I thought. So today I thought I could finally drive it. I made it about a half mile before I seen the temp gauge red lining. So I turned around and parked it at my dads house. When I started it up I notice some faint white smoke from the tail pipe (I know not something anyone wants to see right) but its only about 40° here today so could be steam. I didnt notice it earlier this week when it was warm but I wasn't looking. Last week after changing the transmission I flushed the system with water to get the copper flakes out. The previous owner put in stop leak hoping to fix a radiator leak on the old radiatir. Coolant turned a dark green after I let the engine idle enough to flow through the system to get the rest of the copper flakes out. When the engine gets warmed up it will suck almost all of the coolant out of the reservoir. Then when I shut off the engine, it will dump the coolant back into the reservoir to the point that it is completely filled. Once the engine cools a little bit the level will go back to a normal. After I noticed the overheating tonight and was back at my dads I barely loosened the overflow cap while the engine was idling. As soon as barely got that cap turned it started dumping coolant back into the reservoir. I tightened it back down and it stopped dumping coolant. We checked the oil and its clean (just changed the oil 3 days ago). Didn't notice any coolant in the oil. I shut it off, locked her up and got a ride home. Now I'm wondering where I should start looking for the problem. Thermostat is usually the first thing I check. Tomorrow I'm going to swing back by my dads on my way to town to poke around. Any suggestions on where to start? Link to comment Share on other sites More sharing options...
MiNi Beast Posted April 17, 2021 Share Posted April 17, 2021 start with burping the system again. check flow at upper and lower hoses , (hot or cold) heater core can plug up as well so ensure thats good. can possibly use air to blow it out. some guys use a bypass or gate valve thing in the heater hose to help with burping system and bypassing heater core all together, good to check stat as well have been bad out of a new box (can boil on stove to check if working). ensure no leaks and rad cap is good. also overflow tank should not be full only 1/3 full when good. needs room for the hot coolant to cool down. Some look to a open system from a closed system after a while . Link to comment Share on other sites More sharing options...
Ωhm Posted April 17, 2021 Share Posted April 17, 2021 32 minutes ago, james-mc said: When the engine gets warmed up it will suck almost all of the coolant out of the reservoir. Then when I shut off the engine, it will dump the coolant back into the reservoir to the point that it is completely filled. Once the engine cools a little bit the level will go back to a normal. This symptom is strange. Not sure what it means though. Link to comment Share on other sites More sharing options...
MiNi Beast Posted April 17, 2021 Share Posted April 17, 2021 1 minute ago, Ωhm said: This symptom is strange. Not sure what it means though. air in the system or blockage Link to comment Share on other sites More sharing options...
jdog Posted April 17, 2021 Share Posted April 17, 2021 only other thing i would add is verify it is actually overheating, just because the gauge says it is doesn't mean that it is accurate Link to comment Share on other sites More sharing options...
MiNi Beast Posted April 17, 2021 Share Posted April 17, 2021 2 minutes ago, jdog said: only other thing i would add is verify it is actually overheating, just because the gauge says it is doesn't mean that it is accurate wtf? you saying the gadget reads hot but it might not be...? oh man the fun of driving a heep...jeep. cough..cough.. Link to comment Share on other sites More sharing options...
jdog Posted April 17, 2021 Share Posted April 17, 2021 5 minutes ago, MiNi Beast said: wtf? you saying the gadget reads hot but it might not be...? oh man the fun of driving a heep...jeep. cough..cough.. yep, the joys of 30+ year old vehices Link to comment Share on other sites More sharing options...
MiNi Beast Posted April 17, 2021 Share Posted April 17, 2021 2 minutes ago, jdog said: yep, the joys of 30+ year old vehices and being only a couple years older then my jeep, i sometimes get hot and really I'm not. Link to comment Share on other sites More sharing options...
james-mc Posted April 17, 2021 Author Share Posted April 17, 2021 9 hours ago, jdog said: only other thing i would add is verify it is actually overheating, just because the gauge says it is doesn't mean that it is accurate I thought that too lol. I was looking at new temp sensors while i was on napas site ordering a thermostat. Link to comment Share on other sites More sharing options...
james-mc Posted April 17, 2021 Author Share Posted April 17, 2021 I'm going to try burping it again. I'm hoping its not anything head gasket related. It wouldnt hurt to change tstat i guess since its only 6 bucks for the tstat and gasket Link to comment Share on other sites More sharing options...
jdog Posted April 17, 2021 Share Posted April 17, 2021 Get the one with the jiggle valve or drill a small hole towards the top to assist with bleeding. Link to comment Share on other sites More sharing options...
MiNi Beast Posted April 17, 2021 Share Posted April 17, 2021 jiggle valve? Link to comment Share on other sites More sharing options...
james-mc Posted April 17, 2021 Author Share Posted April 17, 2021 So I was just messing with it. No white smoke from tailpipe. Coolant is greenish and rust colored and will need flushed again. It didnt seem like any oil is mixing with it. But the same issue I'm seeing today is: when the engine heats up it will dump coolant into the overflow to the point it boils over. I left it cracked so it wouldnt crank my tank or blow a hose. As soon as i kill the engine it will suck the overflow tank dang near dry. I start it again, it heats up to about 210ish and the overflow fills to the point of boiling over once again. Has anyone had this issue? I'm trying to burp it by running it without overflow cap and filling the reservoir as it sucks down. It only has one gallon of coolant I put in. Plus whatever didn't completely drain out of the engine when i flushed it. I'm at a loss. Link to comment Share on other sites More sharing options...
jdog Posted April 17, 2021 Share Posted April 17, 2021 2 hours ago, MiNi Beast said: jiggle valve? Link to comment Share on other sites More sharing options...
jdog Posted April 17, 2021 Share Posted April 17, 2021 12 minutes ago, james-mc said: So I was just messing with it. No white smoke from tailpipe. Coolant is greenish and rust colored and will need flushed again. It didnt seem like any oil is mixing with it. But the same issue I'm seeing today is: when the engine heats up it will dump coolant into the overflow to the point it boils over. I left it cracked so it wouldnt crank my tank or blow a hose. As soon as it kills the engine it will suck the overflow tank dang near dry. I start it again, it heats up to about 210ish and the overflow fills to the point of boiling over once again. Has anyone had this issue? I'm trying to burp it by running it without overflow cap and filling the reservoir as it sucks down. It only has one gallon of coolant I put in. Plus whatever didn't completely drain out of the engine when i flushed it. I'm at a loss. are you running a open or closed system? sounds like a stuck thermostat or a clogged/collapsed hose Link to comment Share on other sites More sharing options...
james-mc Posted April 17, 2021 Author Share Posted April 17, 2021 1 hour ago, jdog said: are you running a open or closed system? sounds like a stuck thermostat or a clogged/collapsed hose Its a closed system. Just a coolant reservoir, no radiator cap. Link to comment Share on other sites More sharing options...
Ωhm Posted April 17, 2021 Share Posted April 17, 2021 Water pump direction (flow). Serpentine Belt installed properly. Lower radiator hose collapse. Link to comment Share on other sites More sharing options...
87MJTIM Posted April 17, 2021 Share Posted April 17, 2021 43 minutes ago, jdog said: sounds like a...clogged/collapsed hose 20 minutes ago, Ωhm said: Lower radiator hose collapse. My first thoughts. The water pump may be pulling enough to collapse the lower hose. How old are the hoses? Link to comment Share on other sites More sharing options...
jdog Posted April 17, 2021 Share Posted April 17, 2021 46 minutes ago, james-mc said: Just an overflow not a overflow, that's a coolant reservoir Link to comment Share on other sites More sharing options...
james-mc Posted April 17, 2021 Author Share Posted April 17, 2021 1 hour ago, 87MJTIM said: My first thoughts. The water pump may be pulling enough to collapse the lower hose. How old are the hoses? Its hard telling. They were on there when i got the jeep. Ill have to check and see if any of the hoses collapse. Link to comment Share on other sites More sharing options...
87MJTIM Posted April 17, 2021 Share Posted April 17, 2021 Try squeezing the lower hose (when it's cool). If it is mushy, you should replace it. While it's running, open the throttle and see what the hose does at higher RPMs. Link to comment Share on other sites More sharing options...
james-mc Posted April 17, 2021 Author Share Posted April 17, 2021 12 minutes ago, 87MJTIM said: Try squeezing the lower hose (when it's cool). If it is mushy, you should replace it. While it's running, open the throttle and see what the hose does at higher RPMs. I will give that a try this weekend. Link to comment Share on other sites More sharing options...
jpnjake Posted April 19, 2021 Share Posted April 19, 2021 Last year my 4.0 was running a little hot, and the coolant was awful so we flushed the whole cooling system about 8 times and dropped the temps pretty significantly. it also got out a ton rust from the cooling system. Link to comment Share on other sites More sharing options...
Coyote Posted April 19, 2021 Share Posted April 19, 2021 Might not be the cause of the over heat, but a clogged heater core definitely won't help. Easy to clear the heater core. Just pop the lines off of it where it goes through the firewall. With low pressure water hose, alternate between the top and bottom tubes until it runs clear (might take multiple times and let it run for a few minutes). Link to comment Share on other sites More sharing options...
james-mc Posted April 19, 2021 Author Share Posted April 19, 2021 New tstat and coolant cap is supposed to be here tomorrow. Figured Id start with the cheapest solutions lol Link to comment Share on other sites More sharing options...
Recommended Posts
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 accountSign in
Already have an account? Sign in here.
Sign In Now