HMMWV Overheat Q's and pictures

[Videris]

Update? I know it's only been 3+ years but I've been told I'm impatient.

 

[vitamink]

Lol.

I fixed the trans leak and everything is going swimmingly so I drive it at least weekly. I usually travel about 100+ miles and the temp still registers the same and doesn't boil over or anything. I blew a hose (hose clamp failed) last year and got to see what everheating looks like...the needle pegged right and I put off a spy hunter like smoke screen. BTW you don't realize how much antifreeze is in a hmmwv until you blow a hose and turn it all into smoke and make everyone in indianapolis smell like maple pancakes. Once you fix the hose you'll need to take out a loan to refill it. I haven't swapped the temp sender or gauge yet but I assume everything is fine, just registering high.

 

[Videris]

That's a long time on running that high. I guess you're good then. I have same thing going on with my 6.2 liter right now. Gauge is like 230+ then fan kicks on a cools it to like 225. Never gets below that though. Nothing boiling in the overflow tank. Heat gun is in 200 range pretty much everywhere except thermostat housing. That's at the same as the gauge 225+. I'm leaning towards it being my radiator needing to be re-cored as well as thermostat probably nuked. Coolant is clean and everything kicks on like it should so I'm thinking it's one of those two things if not both. Might be motor just being shot out too but if it is I'll yank it out and dump a duramax in the dang thing and be done with it. Anyway glad you got yours still going strong.

 

[awind]

I am having the same problem with my HMMWV. Gauge goes to 200deg fan kicks on. I even pulled the thermostat right out and get the same results. Hard to believe on a 30deg day it will run that hot with no thermostat. If somebody finds a fix that would be great. I have a 1988 chevy with a 6.2 and gets nowhere's near that hot.

 

[jeffy777]

This looks as clean as could be. I responded not noticing the date. Dummy me.

 

[Davetheplumber]

all you need to do is check the temp of the water in the reservoir when its running hot. I will bet that its only 220ish at the highest. The gauges never read correct.

 

[Aerialfred]

Mine would run hot, 240 plus, until I was told I had a 6.2 fan on the 6.5 engine! It came with the new engine installed but someone got in a hurry and forgot to put on the correct fan. Once I changed the fan it has ran 200 degrees all day long!

 

[vinhvinny]

7th, your gauge is bad....use a thermometer in the overflow tank to see the real temp.

i need to find out the actual temp, also, to know if my gauge is accurate.

My question: seeing that the temp sending unit that goes to the gauge is located on the engine block near the first glow plug and the generator, so should I check the temp by shoot my IR thermometer at that area on the engine block to get an more accurate reading or at the overflow tank as you said above?

thank you so much for you help

vinny

 

[Action]

i need to find out the actual temp, also, to know if my gauge is accurate.

My question: seeing that the temp sending unit that goes to the gauge is located on the engine block near the first glow plug and the generator, so should I check the temp by shoot my IR thermometer at that area on the engine block to get an more accurate reading or at the overflow tank as you said above?

thank you so much for you help

vinny

Read post #46 above....

 

[gcbennet]

I used a cooling system cleaner I bought at a local auto parts store and you wouldn't believe the brown crud that came out when I flushed it afterwards. The heater core was plugged-up with sediment as well, definitely affecting it's efficiency, so I removed and cleaned it out. I pulled the cooler stack and found a nice layer of sticks and leaves trapped between them. Following Retired's advice I took my rad to a local shop and had it professionally cleaned, where 30 years of built-up crud was removed and the innards reconditioned. These things are old school and built to last, so for only around $100 it's good as new and flowing as it should now.

 

[vitamink]

I need to do that as well.

 

[NormB]

I used a cooling system cleaner I bought at a local auto parts store and you wouldn't believe the brown crud that came out when I flushed it afterwards. The heater core was plugged-up with sediment as well, definitely affecting it's efficiency, so I removed and cleaned it out. I pulled the cooler stack and found a nice layer of sticks and leaves trapped between them. Following Retired's advice I took my rad to a local shop and had it professionally cleaned, where 30 years of built-up crud was removed and the innards reconditioned. These things are old school and built to last, so for only around $100 it's good as new and flowing as it should now.

That's next weekend.

I recently pulled the heater core (because the fan was dead and I couldn't get the screws loose until I had the box out and could apply some penetrating oil and a little torque) and, while it was out replaced the air intake plenum (or whatever) and a couple of short hoses. THEN I hooked the little guy up to our laundry room faucet and ran water through one direction and another for about an hour. Let it sit for a while, flushed again, then blew debris out with compressed air and reconnected everything.

Heater works GREAT now.

I tried draining the cooling system but the drain valve only dripped. Can't wait to see how much stuff comes out when I DO use the prestone flush treatment. Got a radiator shop not too far away should something untoward happen.

 

[shawnshumvee]

Lol.

I fixed the trans leak and everything is going swimmingly so I drive it at least weekly. I usually travel about 100+ miles and the temp still registers the same and doesn't boil over or anything. I blew a hose (hose clamp failed) last year and got to see what everheating looks like...the needle pegged right and I put off a spy hunter like smoke screen. BTW you don't realize how much antifreeze is in a hmmwv until you blow a hose and turn it all into smoke and make everyone in indianapolis smell like maple pancakes. Once you fix the hose you'll need to take out a loan to refill it. I haven't swapped the temp sender or gauge yet but I assume everything is fine, just registering high.

Speaking of temp gauges. I don't know if i'm just a bit paranoid or is this a sign of something going on? My gauge gets close to 200. Now it has never hit 200 (Yet) but it gets close. The humvee runs great and no signs of over heating but just seeing what you guys think? I would like to catch it (if anything) yearly. I was thinking to change the thermostat just so i know its good? But here's my Gauge and is this normal?

 

[erasedhammer]

Speaking of temp gauges. I don't know if i'm just a bit paranoid or is this a sign of something going on? My gauge gets close to 200. Now it has never hit 200 (Yet) but it gets close. The humvee runs great and no signs of over heating but just seeing what you guys think? I would like to catch it (if anything) yearly. I was thinking to change the thermostat just so i know its good? But here's my Gauge and is this normal?

View attachment 683305

What is the weather like, recent driving conditions? Mine runs cooler than that on a 65 degree day without the engine working too hard.

 

[shawnshumvee]

What is the weather like, recent driving conditions? Mine runs cooler than that on a 65 degree day without the engine working too hard.

Like 90 today in Wisconsin and i was driving 55mph

 

[teteacher101]

Like 90 today in Wisconsin and i was driving 55mph

I live in WI too and had my Humvee out today as well. My temp gauge was around 220 when the fan kicked on at about 55.

 

[shawnshumvee]

I live in WI too and had my Humvee out today as well. My temp gauge was around 220 when the fan kicked on at about 55.

Yikes! No worries?

 

[teteacher101]

Yikes! No worries?

Nope, even last summer on a hot day she would run around the same and never had any problems.

 

[Action]

My old 1985 HMMWV fan kicked in about 220.

 

[shawnshumvee]

Nope, even last summer on a hot day she would run around the same and never had any problems.

Really? Wow! Most ICE (internal combustion engines) Gasoline that is, run cooler right around 195. But the Humvee's run a big block (6.2-6.5) so yes a little hotter but 220? So apparently this is normal?
I have a 6.5 with about 18K (Thats what the odometers says anyways) and i haven't hit 200 yet, So i'm good, Really Good?