Water temperature gauge spikes to impossible high #s then goes quickly to 180°

[khryslerkid]

The only times that I have had problems with a gauge swinging around is when the system wasn't full of coolant.

Normally the sending unit won't work unless it's submerged in coolant. That's my findings anyway. I've seen a system overheating and there wouldn't be any reading on the guage because the system wasn't full or there was air in it. I guess once it gets up to a certain temp the sending unit will eventually work, I don't know but that must be mighty hot.

 

[440+6]

Ok, this is my ride,...?
Took a 10 mile ride just now.and took temps?..
Took tems as follows..
At the water pump housing 182.5
At top of radiator 183.3. Degree

At bottom of radiator 91 degrees
This is with the engine still running ,
IF YOU HAVE A 10 OR 20 DEGREE DROP YOU ARE FUCKED MY FREIND.

 

[biomedtechguy]

Ok, this is my ride,...?
Took a 10 mile ride just now.and took temps?..
Took tems as follows..
At the water pump housing 182.5
At top of radiator 183.3. Degree

At bottom of radiator 91 degrees
This is with the engine still running ,
IF YOU HAVE A 10 OR 20 DEGREE DROP YOU ARE FUCKED MY FREIND.

I'm not sure what you mean, but I can say that the temperature spike on the gauge hasn't happened in a couple of outings, the last time it happened was about a week ago right after I removed the thermostat and started the car. I don't think I've had a spike since I heard the "GLUG-GLUG" sound come from the engine compartment and right after noticed the radiator went from hot top half/barely warm lower half to uniform hot all over.
It seems like I had a significant air pocket in the radiator? or wherever it was, I heard it when it moved up and made that "GLUG-GLUG" sound, loud enough to hear inside the car.
So...
I am going to get one of the high end, high flow thermostats that have been discussed in this thread. I find the thermostats in that price range with that description look similar.

 

[440+6]

I'm not sure what you mean, but I can say that the temperature spike on the gauge hasn't happened in a couple of outings, the last time it happened was about a week ago right after I removed the thermostat and started the car. I don't think I've had a spike since I heard the "GLUG-GLUG" sound come from the engine compartment and right after noticed the radiator went from hot top half/barely warm lower half to uniform hot all over.
It seems like I had a significant air pocket in the radiator? or wherever it was, I heard it when it moved up and made that "GLUG-GLUG" sound, loud enough to hear inside the car.
So...
I am going to get one of the high end, high flow thermostats that have been discussed in this thread. I find the thermostats in that price range with that description look similar.

Sorry was not refering to you my friend, but to diesel something that quoted me saying at the most 20 deg difference in temp, well i had a 90 deg drop from top to bottom on a 70 deg day.
All bone stock, the way it left the factory.
What I wonder really, is what is going on with your setup, smething is wrong, what it is makes me curious!

 

[440+6]

I'm betting your had an air pocket, and if it's gone your troubles may be over.

 

[biomedtechguy]

I'm betting your had an air pocket, and if it's gone your troubles may be over.

Yeah, it sure seems that way.
I have to install a thermostat though, and the O ringed polished aluminum thermostat housing makes that quick and easy, no scraping, no gasket to change, and I only have to drain a little coolant. I may see if I can turn the top hose upward and see if water comes out the thermostat mount hole in the water pump. I don't know, maybe I'll get lucky.
My point is I hate to have to drain anything out, but that time will come eventually.

 

[biomedtechguy]

Again, so far, so good!
I made some calls, researched some posts in Mopar forums, FBBO included, and although EMP/Stewart tech support explained that "they don't drill the 3 tiny holes in the Mopar thermostat" like they do most of the others because "they don't sell enough of that kind and don't have a jig to hold the T-stat for drilling"

I looked around some more and wound up getting that one anyway. I am tossing the Stant SuperStat away from the GTO too, as that radiator/Wraptor/cooling system setup is giving me trouble too, and it too has a high volume water pump from CVF as does my Roadrunner. It's part number 305, and 180° I thought for a moment about getting the 160° to give the cooling system a "head start" but after pondering it, and seeing my no stat temps run as low as 145° I figured it is either going to keep it cool and close to 180° or not, and all the 180° does is make sure it doesn't go cooler than 180°
Anyway, that and a new factory stock fan shroud are on their way.
Hopefully I won't get another air pocket when I change the thermostat.

 

[dodgeboy440]

Great Progress..........
Its Never Easy ...........BUT......................Worth It !!!
Good Job!
Mopar2YA!
John

 

[Scott431]

For the price, I think everyone should have one of these. I've been using one just like this one for about 15 years. It pulls a vacuum on the whole system then fills by using the vacuum to pull the coolant in.

https://www.amazon.com/UView-550500...op+system&qid=1618378450&s=automotive&sr=1-42

 

[biomedtechguy]

For the price, I think everyone should have one of these. I've been using one just like this one for about 15 years. It pulls a vacuum on the whole system then fills by using the vacuum to pull the coolant in.

https://www.amazon.com/UView-550500...op+system&qid=1618378450&s=automotive&sr=1-42

That is one of the "gizmos" I came across as I was researching the problem. Thanks.

 

[biomedtechguy]

Great Progress..........
Its Never Easy ...........BUT......................Worth It !!!
Good Job!
Mopar2YA!
John

 

[kiwigtx]

I had a problem with a wildly fluctuating temperature gauge a few months ago in my work van - cab-over style engine layout. Turns out my radiator was perforated, and there was no coolant between the radiator and the thermostat. 'Easily' fixed that with a new radiator...done the same day and I drove home that night.

Might I offer a suggestion as an alternative - @andyf has a modified thermostat housing which also has a port for the temperature sender unit - designed for the EFI guys.....but it might be worth a shot - or at least looking at this idea. I only wish he did one for the smallblock MoPar engines...I would buy one.

 

[biomedtechguy]

I had a problem with a wildly fluctuating temperature gauge a few months ago in my work van - cab-over style engine layout. Turns out my radiator was perforated, and there was no coolant between the radiator and the thermostat. 'Easily' fixed that with a new radiator...done the same day and I drove home that night.

Might I offer a suggestion as an alternative - @andyf has a modified thermostat housing which also has a port for the temperature sender unit - designed for the EFI guys.....but it might be worth a shot - or at least looking at this idea. I only wish he did one for the smallblock MoPar engines...I would buy one.

It's a nice item, and I watched part of the Lone Star Mopars YT video about it.
@kiwigtx You know I was just bragging about my polished billet aluminum thermostat housing/water hose neck and the O ring gasket.
I'll have to see how the temperature sender/probe was installed, and see if an adapter was used. I don't know how that could affect my situation if I had an air pocket, other than it would get the probe into the water for sure I guess.
@andyf Can I still use my O ring gasket type water hose neck? Your site says something about using a gasket.

 

[Joseph Musial]

I installed a Wraptor serpentine belt and accessories system in my 440 6bbl 70 Roadrunner last year. Dakota Digital gauge system.
I had to install and remove my Cold Case radiator about 6 times because of a defective electric fan motor, and to fit the largest flex fan I could, as well as install 2 Spahl 10" fans, that finally work reliably w/out burning up.
Anyway, I recycled the antifreeze just about every time because it was new, like not even a day in use. My luck, once I had the combo of fans that worked, I developed a problem. Most often when I am first running the engine, it will spike the temp gauge, to impossible high numbers, sometimes as high as the max temp of 350° I have a Stant Premium thermostat, but I just removed it to take that variable out of the equation.
NOTE: I say "impossible" high temperature readings, but I'm concerned it could be STEAM that is making the temp gauge spike. Once the engine is revved up, either stationary or from driving, the temperature gauge quickly goes to a temperature I'd expect, 180 w/T stat installed, and around 145 with it removed.
So when I removed the thermostat, I also ran the heater, thinking I could get any trapped air out of the cooling system. The temperature went high again, I was squeezing the top radiator hose and the 2 heater hoses, to get air out, check for firmness via pressure, etc.
I turned the engine off. The top hose and top 1/2 of the radiator was hot, but the bottom half was only warm, barely, and I could hold my hand on it. I then heard a "gurgle" sound like an air pocket moved, and the bottom of the radiator immediately came to the same expected hot temperature and the gauge read in the expected range.
So, how can I fix this, and what do you suspect the problem is?

I have a 2004 dodge ram 5.7 hemi and it had a overheating problem. When i loosened the radiator cap , air would come out and the engine would cool off. I took the radiator cap and cut the spring one time and that lowered the amount of pressure that the cap holds on the radiator. You may want to run a compression check on each cylinder , you could have a head gasket problem that is pushing exhaust gas back into the cooling system. Also look at your plugs when you pull them, if a cylinder has a leak, the plug from that cylinder will be clean and white.

 

[biomedtechguy]

You may want to run a compression check on each cylinder , you could have a head gasket problem that is pushing exhaust gas back into the cooling system. Also look at your plugs when you pull them, if a cylinder has a leak, the plug from that cylinder will be clean and white.

AGREED, as that would explain high crankcase pressure at WOT.

 

[RJRENTON]

I had the exact same problem you are having when I plugged the mixing hole under the thermostat.
Apparently that little bit of coolant flashes hot for a a couple seconds while the thermostat reacts.

In a B/RB engine, the "mixing hole" under the t-stat is the t-stat BYPASS and is to remain open to allow the coolant to circulate while the engine is coming up to temperature as determined by the thermostat, at which time the t-stat opens, allowing coolant to circulate.
BOB RENTON

 

[dodgeboy440]

I installed a Wraptor serpentine belt and accessories system in my 440 6bbl 70 Roadrunner last year. Dakota Digital gauge system.
I had to install and remove my Cold Case radiator about 6 times because of a defective electric fan motor, and to fit the largest flex fan I could, as well as install 2 Spahl 10" fans, that finally work reliably w/out burning up.
Anyway, I recycled the antifreeze just about every time because it was new, like not even a day in use. My luck, once I had the combo of fans that worked, I developed a problem. Most often when I am first running the engine, it will spike the temp gauge, to impossible high numbers, sometimes as high as the max temp of 350° I have a Stant Premium thermostat, but I just removed it to take that variable out of the equation.
NOTE: I say "impossible" high temperature readings, but I'm concerned it could be STEAM that is making the temp gauge spike. Once the engine is revved up, either stationary or from driving, the temperature gauge quickly goes to a temperature I'd expect, 180 w/T stat installed, and around 145 with it removed.
So when I removed the thermostat, I also ran the heater, thinking I could get any trapped air out of the cooling system. The temperature went high again, I was squeezing the top radiator hose and the 2 heater hoses, to get air out, check for firmness via pressure, etc.
I turned the engine off. The top hose and top 1/2 of the radiator was hot, but the bottom half was only warm, barely, and I could hold my hand on it. I then heard a "gurgle" sound like an air pocket moved, and the bottom of the radiator immediately came to the same expected hot temperature and the gauge read in the expected range.
So, how can I fix this, and what do you suspect the problem is?

FYI:

There is a thread in another Mopar Column Maybe "Chargers" Where A RB Build Used A Chi-Com Water Pump Housing................
Turns Out The Chi-Com Housing Was Not Quite The Same...........As A Mopar Unit In FLOW!
Check yours against A Factory Unit................
youll see.............

 

[biomedtechguy]

I looked up the manufacturer for the high volume CVF branded pump and it's a name I recognized, but the materials are top notch.
UPDATE: I took the RR for a short ride and when I got back it read "350°" SHORT so now I think there's a short in the temp sender or its wire. May have been part of the problem. The temp was NOT 350, ever!

 

[dodgeboy440]

Remember The Song..........................

"When You're Hot You're Hot"...............................
&
"When You're Not You're Not".................

TaaaDaaaa.............

 

[RJRENTON]

I looked up the manufacturer for the high volume CVF branded pump and it's a name I recognized, but the materials are top notch.
UPDATE: I took the RR for a short ride and when I got back it read "350°" SHORT so now I think there's a short in the temp sender or its wire. May have been part of the problem. The temp was NOT 350, ever!

If/when the temperature ever gets to 350°F, you'd be replacing the heads and head gaskets.... abd maybe even the engine......
BOB RENTON