Coolant Gremlins

[S0CAL]

I can replace the upper and lower radiator hoses and the radiator. After that, I don't know. I am really pissed. Not because of the work I've done, but because it isn't resolved. Uggh.

 

[McBroom]

Nah, oil pressure good, no leaks. Thanks man. This is really freaking me out.

Water pump is good.
Bad T stat.

I Love my 18 Ram 2500 4x4 CC U.S.M.C.(ret) CPL

 

[SYKRAMMAN]

I can replace the upper and lower radiator hoses and the radiator. After that, I don't know.

If the upper n lower hoses aren’t leaking or dry rotten n cracking then there’s no need to replace them, saves yourself a couple bucks.

You can try taking it to a shop to have the system completely flushed. It’s not to expensive from what I recall.

 

[S0CAL]

Water pump is good.
Bad T stat.

I Love my 18 Ram 2500 4x4 CC U.S.M.C.(ret) CPL

That is a CST 180, It's only a few months old, but I did go ahead and order a Jet 180 and it should be here in a few days. I am gonna pull the T-stat, leave its grommet, and run the system to see if the problem goes away. That will let me know if the T-stat is the culprit.

 

[S0CAL]

You can try taking it to a shop to have the system completely flushed. It’s not to expensive from what I recall.

Possibly, but I flushed it just a few months back, running distilled water through it until my drains came out crystal clear. This thing was humming along until just this week. Strange.

 

[SYKRAMMAN]

Possibly, but I flushed it just a few months back, running distilled water through it until my drains came out crystal clear. This thing was humming along until just this week. Strange.

There’s only a few things that could cause over heating and you already did two of them. You said everything is functional as far as the t stat opening and the fan kicking on at temp right, so idk what else would cause this besides a head gasket but you would know if it was that. Maybe bad part out of box? Seen it happen all to often.

 

[S0CAL]

T-stat may be the issue, but I still need to pull it, leave the gasket, and test. I do have a replacement for that Tstat on the way.

As a precaution, I went ahead and ordered a new radiator. It will be here Wednesday. I will go ahead and get upper and lower hoses too. At that point, everything will have been replaced. I am going to do another full coolant flush and replace the HOAT on Wednesday.

It's the craziest thing ever.

 

[Fitz-0518]

I am sure you have checked this. I did this earlier this year. Had to replace the thermostat housing. Picked up a new thermostat just because it made sense. 20 min repair. Fired up, temp rose and then climbed. After thinking how could that possibly be. Next morning pulled the hose and hosing,,,,thermo upside down. In your engine I think you can use a LED light to look inside. Doubt that would happen to you, but an easy quick check.

 

[S0CAL]

I am sure you have checked this. I did this earlier this year. Had to replace the thermostat housing. Picked up a new thermostat just because it made sense. 20 min repair. Fired up, temp rose and then climbed. After thinking how could that possibly be. Next morning pulled the hose and hosing,,,,thermo upside down. In your engine I think you can use a LED light to look inside. Doubt that would happen to you, but an easy quick check.

Yeah funny you say that, I am double-checking that tonight.

 

[crackerjack1957]

Ya got a infrared temp gauge to check top hose vrs bottom?

 

[Hemi395]

I want to say the tstat only goes in one way. Like if you put it in backwards the housing won't bolt up right because the tstat sticks out too much....

 

[S0CAL]

Well, well, well. I pulled the T-stat, left the gasket in, bolted the radiator hose back up, filled the radiator and fired her up. I turned on the heater first, to get the coolant thru the heater core then I went full AC. She never got hotter than 190. I was giddy, so I got behind the wheel and jumped on the freeway. Never above 194, YES! Then I got off, found a vacant parking lot, put her in park and rev'd her to 5K RPMs for 2-3 minutes. 228 is the highest I went. I pulled out and headed back home. 228 -- 225 -- 220 -- 205 -- 190. I was cruising thru town at 40 mph and it was 95 degrees outside.

I undoubtedly replaced a water pump that did not need replacing (but at least it's new and hey I know how to do it now). I am cancelling my order on the new radiator and hoses. I have a JET 180 T-stat coming from Matt at MoesPerformance early this week.

So this CST T-stat looks innocuous enough. No visible defects. Wonder why the failure.

Can I drive this baby until my T-stat comes in? I essentially have to get to operating temperature before I put it in gear?

Thanks everyone for your advice and comments. I really appreciate the insight -- especially to those of you who said that T-stat could be sketchy even if it is relatively new. I will know for certain once I put that Jet T-stat in.

Incidentally, that is 2500 RPMs at 88Mph on 35s with 4.56. So for those worried about redlining on the freeway, nope!

 

[S0CAL]

Water pump is good.
Bad T stat.

I Love my 18 Ram 2500 4x4 CC U.S.M.C.(ret) CPL

Boom

 

[McBroom]

Well, well, well. I pulled the T-stat, left the gasket in, bolted the radiator hose back up, filled the radiator and fired her up. I turned on the heater first, to get the coolant thru the heater core then I went full AC. She never got hotter than 190. I was giddy, so I got behind the wheel and jumped on the freeway. Never above 194, YES! Then I got off, found a vacant parking lot, put her in park and rev'd her to 5K RPMs for 2-3 minutes. 228 is the highest I went. I pulled out and headed back home. 228 -- 225 -- 220 -- 205 -- 190. I was cruising thru town at 40 mph and it was 95 degrees outside.

I undoubtedly replaced a water pump that did not need replacing (but at least it's new and hey I know how to do it now). I am cancelling my order on the new radiator and hoses. I have a JET 180 T-stat coming from Matt at MoesPerformance early this week.

So this CST T-stat looks innocuous enough. No visible defects. Wonder why the failure.

Can I drive this baby until my T-stat comes in? I essentially have to get to operating temperature before I put it in gear?

Thanks everyone for your advice and comments. I really appreciate the insight -- especially to those of you who said that T-stat could be sketchy even if it is relatively new. I will know for certain once I put that Jet T-stat in.

Incidentally, that is 2500 RPMs at 88Mph on 35s with 4.56. So for those worried about redlining on the freeway, nope!

View attachment 134358 View attachment 134359 View attachment 134360

It's not that uncommon for a t stat to go bad. No you don't have to wait for the temperature to come up before you drive it. Get in and go like you normally drive. Run the a/c like u want

I Love my 18 Ram 2500 4x4 CC U.S.M.C.(ret) CPL

 

[Hemi395]

Glad you found the problem and that it's a relatively cheap fix. A new water pump at those miles is probably a good preventative thing to have done anyway.

You can run that no problem without a tstat, especially where you live.

 

[Fitz-0518]

Got to love a great ending. Thanks for an interesting journey.

 

[S0CAL]

Got to love a great ending. Thanks for an interesting journey.

LOL, what a day. Beer:30. Thanks man.

 

[Jwithing]

Just catching this thread. I immediately thought thermostat. I've had a couple jet 180 thermos go bad after 36 to 50k miles. You also need to make sure the burp valve is at the 12 o'clock position. That sucks that you just did a coolant flush, but like you said, at least you know the water pump is good now since that was a matter of time. If I were you, I'd upgrade the radiator hoses while you're at it before you put the new thermo in and top it off. Radiator hoses are another one of those long term/high mileage things and it sounds like you plan on keeping the truck for a long time. Glad you figured it out. You'll be fine without the thermo for now.

 

[SYKRAMMAN]

I turned on the heater first, to get the coolant thru the heater core

There’s no need to turn on the heat to get coolant to flow, the t-stat has a bypass that let’s coolant constantly flow thru the heater core.

Glad you figured it out man, keep the old pump as you probably know already. Nice job n hope there’s no more issues for a while.

 

[JB1]

Well, well, well. I pulled the T-stat, left the gasket in, bolted the radiator hose back up, filled the radiator and fired her up. I turned on the heater first, to get the coolant thru the heater core then I went full AC. She never got hotter than 190. I was giddy, so I got behind the wheel and jumped on the freeway. Never above 194, YES! Then I got off, found a vacant parking lot, put her in park and rev'd her to 5K RPMs for 2-3 minutes. 228 is the highest I went. I pulled out and headed back home. 228 -- 225 -- 220 -- 205 -- 190. I was cruising thru town at 40 mph and it was 95 degrees outside.

I undoubtedly replaced a water pump that did not need replacing (but at least it's new and hey I know how to do it now). I am cancelling my order on the new radiator and hoses. I have a JET 180 T-stat coming from Matt at MoesPerformance early this week.

So this CST T-stat looks innocuous enough. No visible defects. Wonder why the failure.

Can I drive this baby until my T-stat comes in? I essentially have to get to operating temperature before I put it in gear?

Thanks everyone for your advice and comments. I really appreciate the insight -- especially to those of you who said that T-stat could be sketchy even if it is relatively new. I will know for certain once I put that Jet T-stat in.

Incidentally, that is 2500 RPMs at 88Mph on 35s with 4.56. So for those worried about redlining on the freeway, nope!

View attachment 134358 View attachment 134359 View attachment 134360

So Jay was right all along, it was the t-stat, I’m glad you got that figured out.
With that many miles on the water pump, just look at it as preventative maintenance