Engine overheating slightly

[Skyler]

Can a clogged inlet/outlet heater hose cause your engine to overheat by any chance?

im flushing the heater core tomorrow morning but I’m wondering if it’s something else causing this aside from a clogged hose? My thermostat, water pump, rad, are all a year old. Haven’t changed my oil in a while— could this cause an engine to run hotter cuz the oil thins?

 

[JEEPCJTJ]

A clogged heater hose, or heater core for that matter, won't cause any overheating. Old oil won't do it either.

Is yours overheating to the point you better shut it off or is it just running on the warm side?

Did you recently top of the coolant level with the wrong stuff?

Is your radiator blocked off by mud or something else in the grille?

 

[Skyler]

I recently topped the entire coolant reservoir, yes! It was 50/50 antifreeze

not overheating to the point of pulling over and turning the engine off no. Today after being stuck in traffic tho I noticed the gauge fluctuating over 110 about ...normally it sits at 100 or just a tad below it I never seen it go up that high before I don’t think so it’s worrying me a bit.

I lll take a look at the grill tomorrow and see what’s going on — was too cold today for me to inspect. I’m thinking smething may be clogged .... I’m flushing the heater core tomorrow anyhow because I’m getting no airflow from the front vents in my Jeep...

 

[beaufrusetta]

I'm inclined to think your issue of no airflow from the upper vents is due to a vacuum line or something linked in here:

https://wranglertjforum.com/threads/how-to-fix-heat-ac-air-not-blowing-through-center-vents.2887/

I don't think your heater core is your problem...unless the air that blows from the bottom is not hot when you've got your heater cranked up.

 

[Skyler]

I'm inclined to think your issue of no airflow from the upper vents is due to a vacuum line or something linked in here:

https://wranglertjforum.com/threads/how-to-fix-heat-ac-air-not-blowing-through-center-vents.2887/

I don't think your heater core is your problem...unless the air that blows from the bottom is not hot when you've got your heater cranked up.

Even if I have full airflow coming from the two side vents, floor vents, windshield vents? It’s just the two front face vents that’s blowing very minimal air out, slightly warm....squeezing on the inlet and outlet rad hoses attached to the heater core— the inlet is hot, the outlet isn’t even close to being hot.... makes me believe something is clogged ....

 

[beaufrusetta]

Even if I have full airflow coming from the two side vents, floor vents, windshield vents? It’s just the two front face vents that’s blowing very minimal air out, slightly warm....squeezing on the inlet and outlet rad hoses attached to the heater core— the inlet is hot, the outside isn’t even close to being hot.... makes me believe something is clogged ....

Yeah - that sounds like a clogged heater core. Flush it in reverse (disconnect heater core hoses, push water through outlet to potentially drive out the gunk collected on the inlet side)...low pressure...see if you get any gunk out of it. I still don't know why that would affect the air movement from your vents...then again, I'm still a TJ-Jedi in training.

 

[Skyler]

Yeah - that sounds like a clogged heater core. Flush it in reverse (disconnect heater core hoses, push water through outlet to potentially drive out the gunk collected on the inlet side)...low pressure...see if you get any gunk out of it. I still don't know why that would affect the air movement from your vents...then again, I'm still a TJ-Jedi in training.

After flushing it and it doesn’t fix the Center vent flow I’m going to check out the blend door actuator

 

[Oklahomacheapjeep]

What psi is your radiator cap set for?

 

[Skyler]

What psi is your radiator cap set for?

I can’t remember id have to check tomorrow but it’s definitely all good there. I haven’t noticed any issues with my cooling system until today....I have restricted airflow to my Center vents(very little Force), when I squeezed on the heater core hoses inlet/outlet, the inlet is hot and the outlet is not even close to being hot which seems odd to me....I think both should be about the same temp and they arnt.... I feel this is causing a circulation problem with the cooling system entirely even if it is only the heater core/hose that could be clogged....


I just read this too....

 

[Oklahomacheapjeep]

I can’t remember id have to check tomorrow but it’s definitely all good there. I haven’t noticed any issues with my cooling system until today....I have restricted airflow to my Center vents(very little Force), when I squeezed on the heater core hoses inlet/outlet, the inlet is hot and the outlet is not even close to being hot which seems odd to me....I think both should be about the same temp and they arnt.... I feel this is causing a circulation problem with the cooling system entirely even if it is only the heater core/hose that could be clogged....


I just read this too....

View attachment 200672

I just ask because after I swapped out my radiator it ran 10-20 degrees hotter because it had a 14 psi cap instead of a 18

 

[IAmTodd]

New mopar radiator cap. Cheap and easy to replace as a start. I had problems with mine boiling and that instantly fixed it.

A non-mopar radiator was installed before my ownership and is on the list to be swapped out. I still run a little hot when stuck in traffic with the A/C on.

 

[MrMark52]

I recently topped the entire coolant reservoir, yes! It was 50/50 antifreeze

not overheating to the point of pulling over and turning the engine off no. Today after being stuck in traffic tho I noticed the gauge fluctuating over 110 about ...normally it sits at 100 or just a tad below it I never seen it go up that high before I don’t think so it’s worrying me a bit.

I lll take a look at the grill tomorrow and see what’s going on — was too cold today for me to inspect. I’m thinking smething may be clogged .... I’m flushing the heater core tomorrow anyhow because I’m getting no airflow from the front vents in my Jeep...

Mmmmmm - that seems kind of weird. I would be more suspect of a dirty radiator, failing fan clutch, or worse, a plugged up radiator - although what was the ambient air temperature when it read 110C (note you say “it’ was too cold today for me to inspect”), I’m having trouble understanding.

110C (230F) doesn’t sound too hot to me. But if the engine has overheated at some point for any one of several reasons, the thermostat is easy to change for minimal cost. Do not put anything cooler or hotter than a 195F (90C) thermostat no matter what anyone else tells you (engine cooling thermodynamics is hard for most to understand). Stat’s that have been overheated are prone to fail closed. 130C tells me it isn’t closed, and that the engine is not overheating. Most car manufacturers don’t consider an engine overheating until the temps gauge needle gets into the red.

”I’m flushing the heater core tomorrow because I’m getting no air flow from the front vents in my Jeep”? Coolant flow thru the heater core has nothing to do with air flow from the vents. You need to check that the blower is running. If not, check the blower resistor module which is behind the glove box and associated plug wiring.
Finally, the air flow from the dash vents on my ’03 TJ is terrible - all due to a poorly designed dash air ducting system.

 

[MrMark52]

Even if I have full airflow coming from the two side vents, floor vents, windshield vents? It’s just the two front face vents that’s blowing very minimal air out, slightly warm....squeezing on the inlet and outlet rad hoses attached to the heater core— the inlet is hot, the outlet isn’t even close to being hot.... makes me believe something is clogged ....

If one coolant hose is cold while the other is hot - then you either have

A) a lot of cold air blowing thru the heater core
B) no coolant flowing thru the heat exchanger, or
C) (am not sure if TJ’s have one) the coolant control valve is for the most part, closed (there has to be some flow for the hose to get warm - for reasons too detailed to explain here ).

With you previous comment about the engine running hotter than normal, it may be that the coolant system may be clogging up. I had this happen on a ‘97 Jimmy. I don’t know what caused it, but the coolant “jelled” up in the system. Never did get it cleaned up before I traded it, even with flushing and a new radiator.

 

[MrMark52]

After flushing it and it doesn’t fix the Center vent flow I’m going to check out the blend door actuator

Other than for tempering the air, coolant flow and air flow are independent of each other.

I would be suspect of the blend door actuator.I seem to remember reading on another thread here about this being an issue on TJ’s, and a fix for it. Do a search on “blend door”.

 

[MrMark52]

What psi is your radiator cap set for?

Increasing cap pressure does nothing more than allowing the coolant to get hotter before it boils, not to forget forcing the engine to run outside of the preferred operating temperature range.

Increasing cap pressure can also cause a premature failure of coolant system components. While those components might can handle the higher pressure, a properly functioning engine and coolant system do not require higher pressures.

 

[MrMark52]

New mopar radiator cap. Cheap and easy to replace as a start. I had problems with mine boiling and that instantly fixed it.

A non-mopar radiator was installed before my ownership and is on the list to be swapped out. I still run a little hot when stuck in traffic with the A/C on.

If it boiled over, and you said in another comment that a PO had replaced the radiator with aftermarket, and yet another comment that you don’t think your getting coolant flow thru the heater core - I would be real, real, suspect that your coolant system may be all gunked up. As Oklahomacheapjeep suggested, be sure to back flow flush the heater core, and watch for gunk coming out initially. If you see gunk, you might want to reconsider that radiator replacement for sooner than later (and when you do, be sure to reverse flush the heater core again. And don’t forget to do the same to the block since you should be replacing the thermostat at the same time).

 

[Skyler]

WOW!!! No freaking wonder LOL. Zip ties to the rescue

 

[IAmTodd]

If it boiled over, and you said in another comment that a PO had replaced the radiator with aftermarket, and yet another comment that you don’t think your getting coolant flow thru the heater core - I would be real, real, suspect that your coolant system may be all gunked up. As Oklahomacheapjeep suggested, be sure to back flow flush the heater core, and watch for gunk coming out initially. If you see gunk, you might want to reconsider that radiator replacement for sooner than later (and when you do, be sure to reverse flush the heater core again. And don’t forget to do the same to the block since you should be replacing the thermostat at the same time).

When I did the cap I also did a coolant flush with G05 flushing the heater core and also draining the block. Minimal crud. New coolant is still clear after a few thousand miles.

I'll be doing a mopar radiator, water pump, and thermostat in the spring. I do suspect my PSC coolers are killing the air flow though.

 

[TheBoogieman]

So much bad information here I don't know where to start. I hope you got it fixed with the fan shroud.

 

[Skyler]

So much bad information here I don't know where to start. I hope you got it fixed with the fan shroud.

Right? It’s pretty appalling for a Jeep forum to say the least. And if I interject I get attacked and bullied by trolls LOL

shroud was fixed and core was flushed— have air from my vents now