Replaced Everything twice. Still overheating

[GreatOdin'sRaven]

I’ve been chasing an overheating problem going on three years.

Jeep overheats at idle.

Every summer my Jeep overheats, I change parts all summer and never fix it until the weather cools down and the problem goes away.

2018:
-moved to Las Vegas and my overheating problems begin
-replace every cooling system part one by one with cheap Chinese stuff.
- find leaking head gasket in Oct, repaired it
- head checked for leaks/cracks, replaced with felpro gasket using new bolts.


2019:
-overheating begins around May
- replace each cooling system part (again) one by one, but with OEM or better parts
- chase problems down all summer until weather gets cool

2020:
- overheating problems starting again this week
- super cleaned my AC condenser
- Still overheating at idle



Here’s what I’m running/replaced - (consider all parts brand new and less than one year old)

**RADIATOR**

OEM from AutoZone
Silicone hoses top and bottom from Amazon


**FANS**

HD fan clutch from Napa for ZJ
Low profile 10 inch E fan (turns on at 218 F)


**WATER PUMP**

Flowkooler high flow water pump



**THERMOSTAT**

Super Stat 180 degrees
Hesco High flow thermostat Housing


**OTHER**

-Cleaned the AC condenser for about 3 hours
-I’ve ran Preston flush more times than I can count
- My heater is not by passed (heat works fine)
- I’ve ran compressed air through every hose backwards and forward multiple times
- I don’t have that stupid spring in the bottom hose but doubt that’s causing my problems
- i verified it is actually overheating using a IR heat gun pointed at thermostat housing


Any help is greatly appreciated. I am about to drive the Jeep off a cliff. I am even desperate enough to take it to a mechanic at this point.

Please help.

 

[lawsoncl]

Well, you wouldn't be the first person to cause an overheating problem by installing a high-flow pump and housing. Are you running lean, or torque converter slipping? Just trying to separate overheating from poor cooling, or generating too much heat.


A high-flow pump and not having the spring in the bottom might cause it to collapse at higher rpm, but you said this is an overheating at idle problem.

 

[RCP Phx]

Questionable on the radiator, but install a 195* t-stat and check the heater core, ditch the wp for a Hesco and the fan clutch would be in question(do you have a part number)?

 

[RCP Phx]

BTW, the trans can overheat the system also, what gearing and tire size do you have?

 

[RCP Phx]

Also, what year are we talking about?

 

[devildog0]

If everything else is working ok then the Spectra rad from Autozone or whoever should work fine.

Also curious about tires and gearing.

I'd swap back to a stock non high flow waterpump, and go back to a normal 195 degree t-stat.

What's going on when it starts overheating? Only overheating at lowspeed/idle? Only at highway speeds? All the time?

 

[old_man]

My bet would be on the silicone hoses. Even regular lower radiator hoses are known to collapse when hot. That is why the OEM hoses had a spring inside to keep this from happening. Find a spring or get a stiffer hose.

 

[CJR]

"- find leaking head gasket in Oct, repaired it
- head checked for leaks/cracks, replaced with felpro gasket using new bolts"

Some questions for you:

1. What year and engine are we talking about?
2. Did you just replace the head gasket? Or did you have the head pressure-tested for leaks and then have the head's gasket surface reground?
3. Tell me, in detail, how you installed the head gasket?
4. What type of head-bolts did you use? Torque-to-yield, use only once, and discard bolts?
5. What was the maximum water temperature you measured with your IR temperature measuring gun?
6. Did you use the "exhaust gas sniffer kit", at the open radiator fill nozzle, available at NAPA, to "sniff" for exhaust gas getting into your anti-freeze/coolant?
7. With your IR gun, did you look at your head for excessive high temperature spots? If so, where were the hot spots located? Were any hot spots located near head bolts?

Best regards,

CJR

 

[Unclewolverine]

Definitely change to the 195 stat. You are probably not getting out of warm up mode on the computer at 180.

 

[GreatOdin'sRaven]

Let me clarify a few things, sorry:

1999 6 cyl

The tires and gears don’t matter Bc this this will overheat at idle. If I removed the tires and gears, it will still overheat in my driveway.

Also. I changed parts one at a time...

Meaning it was overheating with the 195 thermostat, remove, replace with 180, still overheats. Even Overheats with no thermostat

Same with low flow or high flow water pump. Overheats with or without.


I’m also running an after market trans cooler up front.


It’s a slow creep upwards. Gets to 210 slowly. Eventually the fan comes on and is able to keep the temps around 218-220 but loses that battle on hot days and goes up to 230 where I turn off the Jeep and go cry for a little.


Sent from my iPhone using Tapatalk

 

[RCP Phx]

**FANS**

HD fan clutch from Napa for ZJ
Low profile 10 inch E fan (turns on at 218 F)

Besides the question on the ZJ clutch, most non-factory e-fans don't pull enough air.

 

[GreatOdin'sRaven]

"- find leaking head gasket in Oct, repaired it
- head checked for leaks/cracks, replaced with felpro gasket using new bolts"

Some questions for you:

1. What year and engine are we talking about?
2. Did you just replace the head gasket? Or did you have the head pressure-tested for leaks and then have the head's gasket surface reground?
3. Tell me, in detail, how you installed the head gasket?
4. What type of head-bolts did you use? Torque-to-yield, use only once, and discard bolts?
5. What was the maximum water temperature you measured with your IR temperature measuring gun?
6. Did you use the "exhaust gas sniffer kit", at the open radiator fill nozzle, available at NAPA, to "sniff" for exhaust gas getting into your anti-freeze/coolant?
7. With your IR gun, did you look at your head for excessive high temperature spots? If so, where were the hot spots located? Were any hot spots located near head bolts?

Best regards,

CJR

Hey CJR,

I found an old list that I followed couple years ago I posted below.

1: year - 99, 6 cyl

2: head gasket was pressure tested and checked for leaks and cracks by the most recommended shop on Vegas, it wasn’t cheap.

3: how I installed: list below, I remember planning this forever, followed the FSM to the T. I was proud of myself.

4: bolts I used: https://m.autozone.com/internal-eng...-pro-head-bolt-set-es71102/571881_0?rrec=true

Says they are TTY torque to yield bolts

5: Maximum temp recorded? I honestly don’t remember. I use a Bluetooth ODB plug that reads me temps on an app called dash command. I have compared the IR temp gun reading with the app reading and cool, warm, hot and too hot and they are usually 1-2 degrees off. So I trust what the app tells me. I remember it getting up to 240 or maybe more past summer.

6: Did I use sniffer kit: Idid last summer, I actually own a sniffer kit (so pathetic) - this is how I found my head gasket was blown the first time. I ran it a few times last summer and the liquid didn’t turn green. (this is when I put the tube of liquid in the radiator right?)


7:Using IR gun for hotspots on head: no I haven’t done that, but that might be a good thing to do. Will do that soon and report back.

Sent from my iPhone using Tapatalk

 

[GreatOdin'sRaven]

Besides the question on the ZJ clutch, most non-factory e-fans don't pull enough air.

I ran this one in 2018:

TYC 620560 Jeep Cherokee... https://www.amazon.com/dp/B000IYNVN6?ref=ppx_pop_mob_ap_share


Then swappeed it out for this one in 2019: Maxiii 10 Inch Radiator Cooling... https://www.amazon.com/dp/B07VX5V43P?ref=ppx_pop_mob_ap_share

Both of them overheated before and after


All of this has really slowed down how long it takes to overheat. But still overheats in the end.


Sent from my iPhone using Tapatalk

 

[GreatOdin'sRaven]

Well, you wouldn't be the first person to cause an overheating problem by installing a high-flow pump and housing. Are you running lean, or torque converter slipping? Just trying to separate overheating from poor cooling, or generating too much heat.


A high-flow pump and not having the spring in the bottom might cause it to collapse at higher rpm, but you said this is an overheating at idle problem.

Hmmm, not sure if I’m running lean. How would I check that?

My torque converter seemed like it was slipping a few weeks back. Changed my MAP sensor and that fix es that. Mind you overheating was an issue before and after MAP sensor.

Also, about the highflow water pump. Jeep overheated before the water pump was installed. This was one oft that greatly helped the time before it started overheating.

I could swap back to stock. But I know it will still be overheating like it did before.


Sent from my iPhone using Tapatalk

 

[CJR]

My comments to your response is based on my experience with XJ head gasket leaking. Many years ago I bought a used 88XJ which ran hot on hot days. Since the car was under warranty, I contacted the dealer and he offered to have it pressure-tested to check the head gasket. My car checked-out to be OK after pressure testing and I picked it up on a very hot day. I did some very hard accelerations, and saw a puff of white smoke out the exhaust which then stopped when I backed-off on the throttle. Under normal driving I got no white smoke. White exhaust smoke only appeared momentarily when I did hard acceleration and ended when I backed. I called the dealer and explained what happened and he requested the car back. My head was then removed, pressure-tested again and the head's gasket surface was ground flat. The head was re-installed and no more overheating episodes occurred.

Here's an old hot-rodder's tip I use for installing new MLS (multi-layer-steel) head gaskets on resurfaced heads:
1. I clean the engine & head surfaces with lacquer thinner repeatedly until I can wipe the surfaces with a clean paper towel and the paper towel remains white with no dirt on it.
2, The pores of the cast iron are now clean and ready to "grip" the three (3) coats of aluminium stove-pipe paint that I apply.
3. The MLS gasket is also aluminium paint coated and dropped on the engine followed by the head. The head is torqued according to spec. Then retorqued a number of times so that the torque
reading is stable. Remember after heat cycling, the gasket & paint compresses down as the bolts settle into the head.

This technique allows the head to thermally expand/shrink horizontally , on the aluminium painted block, and maintain the gasket seal. In my view, the worst head gasket to use is a teflon-coated gasket. What happens is that the teflon bites into the pores of the cast-iron and "locks" the teflon from moving. During thermal cycling, the soft teflon coating expands/shrinks and fatique fails quickly and micro-cracks occur in the teflon coating which then become pressure leakage paths and result in a leaking head gasket. Years ago most all head gaskets were multi-layer-steel gaskets that were painted with stovepipe aluminium paint. We didn't have rampant head gasket failures like today.

TTY bolts. There is data readily available showing how high temperatures reduce the Young's Modulus of Elasticity of all materials. The head is the hottest part of an engine. Therefore, if a TTY bolt is overheated it can stretch and "take a set"(i.e.can be longer in length) and it will no longer provide the necessary "clamping force" to keep the head gasket sealed. I do not use TTY head bolts any more; I only used older XJ head bolts or new ARP head bolts.

Best regards,

CJR

 

[GreatOdin'sRaven]

CJR,

I really appreciate the insight. I think what you’re saying is that given all the details, I’m most likely looking at a head gasket issue.

This will be the third time that I replace the head gasket.

I’m wondering if I should just throw a clearwater head in there instead of having my cylinder head checked for the third time in as many years.

https://www.cylinder-heads.com/product/new-jeep-cherokee-laredo-4-0-0331-cylinder-head-complete/


If I end up doing another gasket replacement, I’ll avoid the TYY bolts.


Sent from my iPhone using Tapatalk

 

[CJR]

Typically, resurfacing a head and re-installing the gasket/head properly is a lot cheaper than buying a new head. Just because a head is new is no assurance the head's gasket surface is straight. It can either be checked with a precision ground bar and feelers gauges placed between the bar and head. Or the head can be "dykem-coated" and a long precision ground bar rubbed over the head surface to see where the high/low spots are and how flat the new head really is. Heads, with minor warp, can be sanded on precision flat ground marble slabs and trued-up. Good luck on your effort.

Best regards,

CJR

 

[GreatOdin'sRaven]

***SOLVED***

It was the head gasket.

So I didn’t want to believe that it was the head gasket that I so meticulously installed at the end of 2018.

Why not?

1) The cylinder compression was good
2) the combustion leak test was good (liquid never turned green)
3) I used quality parts and followed the FSM to the T when I installed

BUT. I did have minor coolant loss and everyone was talking me it has to be the head gasket.


I used Blue Devil head gasket sealer as a test to see if it would help. and I’m proud to say my Jeep no longer overheats.

I will have to properly repair the head gasket soon.

Lesson learned: just because the block tester isn’t telling you that you have a head gasket leak, doesn’t mean it’s not leaking.

Thanks for the help and attention guys!