Water temp rises to 240 real quick....hmm

[HOOKED ON GT]

Driving in central FL today just nice and easy for about 30min (fwy/local traffic).
Pulled over to park and noticed car was at about 200 deg so about normal.
5min later I come out and drive in the lot for 1min and have to back up (too steep exit slope) and notice steam on the rear glass when I turn my head.
Pull out of the parking lot and check temp and see it at 240 (no limp mode).
Pull over and lift shell and let it rest but as I open it I notice its belching coolant out the degas bottle for about 5 sec.
I get some water at Publix next door and add about a gallon after its cooled for awhile.
Start it up and its cool for a few min and then I see the temp dial rising quick to 200+ (just idle)

Have a friend who has a shop I use for my other cars close by and he turns on the heat to max and then the temps drop quickly.
Let it cool again and I get another 1/2 gallon into the baffle mark at indicator level (once rested again).

His thoughts are that the thermostat might have been stuck and once free things cooled?
And the addition of water beyond what I lost in the initial steam/water exit over 1.5 gallons might suggest I had a decent air pocket that moved and the extra water helped?

Drove home and temps in traffic get to about 220 but could pull it back when heater is on.

Id just done a new water pump few weeks ago and this drive was the first decent length it had been used and Id not lost much with the replacement of the pump but refilled to lower baffle with more then id lost by miles..... so thought all was fine.

Id noticed some gurgling coming from the system when the car was turned off past few drives (not temp issue on gauge)

 

[nota4re]

After water pump install, how did you re-fill coolant?

Check that fans are running up front. Easiest way is to turn on AC and fans should be screaming. Are they working?

A faulty thermostat would not be high on my suspect list... yet.

 

[HOOKED ON GT]

Refilled through degas bottle

Yes fans running fine

My friend did a OBD test and triggered them to start.

SA

 

[GT Tech]

Did you use a vacuum rig to refill the coolant? Unless you used it, you will never get all the air out of the system. Trust me, we tried. There is a petcock on the top of the rad. Just for a test, we tried to bleed it through there to no avail. They were all filled using a vacuum set up at the factory.

 

[nota4re]

Refilled through degas bottle

I think that's your problem (and the reason I asked).

Because you did not fill using a vacuum method, you likely have air trapped in the system. The correct vacuum fill tool is what you need. The original tool was made by Snap-on and called RADKITPlus or something like that. You can get different brand kits that work just as well. No need to drain again - just use the tool and it will insure that any air bubbles get removed. Here's a link to one of the tools on the lesser expensive side. RadKitPlus

 

[PL510*Jeff]

You should also get new caps. Once they vent, just like on your water heater, they will operate much sooner, and may not close completely.

 

[twobjshelbys]

The symptoms wreak of water pump. Are you sure its good?

 

[HOOKED ON GT]

Yep... I think it had gut bomb of air in there hence the gurgle sounds I had started to hear once shut off.

I have a RADKIT and used it last fluid change early 21 but I didn't get near the OE volume back in (think thats common?)

My next change I'll use the front petcock for max air exit in system (didnt last change)
I think its the suck up point once its negatively pressured back to bottle?

Pumps brand new so should be a champ for years to come

Thanks for the help on the tricks the cooling system seems to have.

Cheers Stuart

 

[dr914]

I started to read this and immediately thought thermostat until further down the story when you said you just replaced the water pump. NOW I would say that the cooling system was not bled properly / thoroughly and you have a bubble in the cooling system. This same thing happens in the water cooled front radiator rear engined Porsches. Proper bleeding by the book is critical

 

[B.M.F.]

Yep... I think it had gut bomb of air in there hence the gurgle sounds I had started to hear once shut off.

I have a RADKIT and used it last fluid change early 21 but I didn't get near the OE volume back in (think thats common?)

My next change I'll use the front petcock for max air exit in system (didnt last change)
I think its the suck up point once its negatively pressured back to bottle?

Pumps brand new so should be a champ for years to come

Thanks for the help on the tricks the cooling system seems to have.

Cheers Stuart

When you drain the coolant system the air pocket gets in the main line to wp and you will have hot water all the way to the drivers side of radiator where small hose meets it, but the big bottom hose on pass side will be cold cause water pump is not pulling any water.

IMO the top bleeder on radiator would need to be 1/2 or 5/8 to release enough air to get rid of the air pocket.

Best way to fill the car with coolant with out sucking the air out is to jack the rear of the car up as far as you can.

As soon as coolant circulates whatever small air pockets that may be left will bleed out.

 

[GT@50]

When you drain the coolant system the air pocket gets in the main line to wp and you will have hot water all the way to the drivers side of radiator where small hose meets it, but the big bottom hose on pass side will be cold cause water pump is not pulling any water.

IMO the top bleeder on radiator would need to be 1/2 or 5/8 to release enough air to get rid of the air pocket.

Best way to fill the car with coolant with out sucking the air out is to jack the rear of the car up as far as you can.

As soon as coolant circulates whatever small air pockets that may be left will bleed out.

Watch the splitter on the front as you go up in the back.

 

[B.M.F.]

Watch the splitter on the front as you go up in the back.

Always do that too.

 

[HOOKED ON GT]

When you drain the coolant system the air pocket gets in the main line to wp and you will have hot water all the way to the drivers side of radiator where small hose meets it, but the big bottom hose on pass side will be cold cause water pump is not pulling any water.

IMO the top bleeder on radiator would need to be 1/2 or 5/8 to release enough air to get rid of the air pocket.

Best way to fill the car with coolant with out sucking the air out is to jack the rear of the car up as far as you can.

As soon as coolant circulates whatever small air pockets that may be left will bleed out.

I did the jack ass up idea but not sure it went well.
it holds 8 gallons I think but getting that out/in is impossible.
Parking the car on a real steep hill would be ideal when refilling
Whack it on the back and burp her would help