[P38] Exhaust gases in coolant

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I've pumped the tool by itself, will keep an eye on it.

Finished reassembling, started up and seems to be running okay. No leaks so far.
It did start to overheat after about 10 minutes, but I was expecting that because I haven't refilled the coolant properly yet.

Will try tomorrow and see how it goes. Hopefully no leaks appear under the car overnight
 
No leaks overnight.

Drained coolant today via rad plug, and slowly refilled with just water for now.

Followed the process in RAVE - but when I ran it again the temperature was averaging around 117-118C, which is decently outside normal range I believe?

Reading was made via obd tool - temp needle on the dash was still steady in the middle.

20250501_141845.jpg
 
The car is pre OBD so there's a chance it's not reading properly..... maybe? Thermostat should be fully open at 96c so you're way above that.

The coolant sensors only sense up to 130c, so you'd have thought the dashboard one was well above normal by 118c.

Was it otherwise running fine?
 
It seems to be running fine - but I haven't left it running for too long just in case it was getting too hot.
Upper rad hoses were scalding to the touch, but not rock solid, only quite hard.

Once it's cooled I'll double check the levels and give it another go.
 
blue_cheese said:
No leaks overnight.

Drained coolant today via rad plug, and slowly refilled with just water for now.

Followed the process in RAVE - but when I ran it again the temperature was averaging around 117-118C, which is decently outside normal range I believe?

Reading was made via obd tool - temp needle on the dash was still steady in the middle.

View attachment 340096
Click to expand...
where was the needle on the temp gauge?

thats WAY WAY too hot for a rv8
 
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Just went out again and topped up the water.

Ran for about 10 minutes, temperature reading on the device was in the high 90s, possibly very slowly creeping up.
Dash temp gauge in the middle.

Noticed the blowers weren't that hot, so possible that there's still air trapped somewhere.
Is there a way to bleed the remaining air? Or is it a case of draining it and starting again?
 
I’ve never had a problem by just following the RAVE procedure. Squishing the top hose can help certainly. Repeatedly to force coolant about. It can help burp it I’ve heard.

Also giving it a good rev to really set the coolant moving.

Also the coolant always circulates through the heater matrix, no matter what the temp controls are set to. So you should feel hot water going through the two pipes that go through the firewall into the cabin. If they’re not getting hot you’ve either got a blockage, or the water pump isn’t pumping. Something would be wrong anyway.
 
MrGorsky said:
I’ve never had a problem by just following the RAVE procedure. Squishing the top hose can help certainly. Also the coolant always circulates through the heater matrix, no matter what the temp controls are set to. So you should feel hot water going through the two pipes that go through the firewall into the cabin. If they’re not getting hot you’ve either got a blockage, or the water pump isn’t pumping. Something would be wrong anyway.
Click to expand...
On the diesel, raising the front of the car helps with the bleeding.
 
Just been out again and ran it for a while with the cap off to let any air escape.

Still idled in the middle of the temp gauge.

I noticed that the right side pipe to the cabin was hot, but the left side pipe was not. Possible air in the cabin loop?

20250501_174846.jpg
 
It's a bit of a faff but yes i found on my 4.0 it was always easier to drain down and start again.
Check the small pipes that run across to the throttle body aren't blocked and the throttle body itself (it is a v8 isn't it? I forgot)
 
Did you follow the RAVE fill procedure ? If not, then you will almost certainly have an airlock.

Are you getting flow through the small pipe from the radiator to the coolant tank ? Also did you clear it before starting the fill ?

As others said you should have hot coolant flowing to the heater all the time, and slightly less hot flowing back. Probably only a few degrees, so both hoses will feel hot to your hands.

Try another OBD reader just in case. 110C is about to boil over & probably near the coolant cap release point.
 
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