[P38] Exhaust gases in coolant

[kermit_rr]

When you fill the radiator, disconnect the bleed pipe at the radiator, does coolant come out?

 

[blue_cheese]

When you say fill the radiator, do you mean fill it directly through the top hose?

 

[Grrrrrr]

Afternoon,
I've had another go at filling the coolant.
I drained as much as I could from the radiator, and made sure the bleed hose was clear.
Filled up until it was at the neck level, then started the engine.
Filled up a little more after a minute, until it was fairly steady on the cold level line.

How long should I be waiting for the thermostat to open? I waited about 7-8 minutes, until the top hose was quite hot, by that time the coolant started gushing out of the expansion tank so I shut off the engine. Is that supposed to happen?

Also noticed the interior blowers weren't that warm either.

I filled and then sat squinting under the bonnet at the expansion tank. Hood the revs at 1800 rpm unless it starts splashing and jump out every so often to top it up

 

[Grrrrrr]

Just ran it again until it started going in to the red.
Coolant still gushing, heaters on full blast max temp.

Noticed that radiator feels cold all over - no hotspots on the top or bottom (from the limited places I could feel it anyway)

Heaters won't matter. The pipes to the matrix are permanently open with the air mix changed in the cabin as required.

 

[blue_cheese]

Just tried it again after leaving it for a while.

Tried filling via radiator top hose, but it was already full. The metal pipe on the other end that goes to the block was also full.
Started it up, ran for a few minutes before coolant was being pushed out of the expansion tank.
Turned it off and put the cap back on, started it up again and ran for a few more minutes before starting to creep in to the red.

When you fill the radiator, disconnect the bleed pipe at the radiator, does coolant come out?

Coolant was coming out when the engine was warm.

I did notice a few things:
- Radiator was still quite cold, despite top hose being scalding hot.
- Top hose was quite hard, not rock hard but a bit stiff
- Inside the car, I could hear this odd noise:


Any ideas are welcome

 

[kermit_rr]

Just tried it again after leaving it for a while.

Tried filling via radiator top hose, but it was already full. The metal pipe on the other end that goes to the block was also full.
Started it up, ran for a few minutes before coolant was being pushed out of the expansion tank.
Turned it off and put the cap back on, started it up again and ran for a few more minutes before starting to creep in to the red.


Coolant was coming out when the engine was warm.

I did notice a few things:
- Radiator was still quite cold, despite top hose being scalding hot.
- Top hose was quite hard, not rock hard but a bit stiff
- Inside the car, I could hear this odd noise:


Any ideas are welcome

With the bleed pipe disconnected from the radiator and the cap off the expansion tank, coolant should flow from the radiator easily. Blow down the bleed return hose to ensure it's completely clear of coolant, then reconnect to the radiator.
Start the engine, with the cap off, you should see a slight dribble from the bleed return, raise the revs to 1500-2000 rpm and it should 'wee' a steady stream.
With the engine off.. squeeze and hold the top hose, place a finger over the bleed return hole in the filler neck, release the top hose, remove finger. Repeat several times. See if the level drops in the expansion tank

 

[kermit_rr]

If you're feeling frisky...
When it's cold..
Finger over the overflow, blow into the expansion tank with as much puff as you have, then pull away. Quick incase it regurgitates in your mouth
Don't ask me how i know this bit it's very successful at getting air out.

At this point i think you've still got an 'exhaust gas in the coolant' problem.

A healthy sniff should give it away to be honest

 

[Datatek]

Just tried it again after leaving it for a while.

Tried filling via radiator top hose, but it was already full. The metal pipe on the other end that goes to the block was also full.
Started it up, ran for a few minutes before coolant was being pushed out of the expansion tank.
Turned it off and put the cap back on, started it up again and ran for a few more minutes before starting to creep in to the red.


Coolant was coming out when the engine was warm.

I did notice a few things:
- Radiator was still quite cold, despite top hose being scalding hot.
- Top hose was quite hard, not rock hard but a bit stiff
- Inside the car, I could hear this odd noise:


Any ideas are welcome

Are you sure that the radiator is not blocked?

 

[blue_cheese]

With the bleed pipe disconnected from the radiator and the cap off the expansion tank, coolant should flow from the radiator easily. Blow down the bleed return hose to ensure it's completely clear of coolant, then reconnect to the radiator.
Start the engine, with the cap off, you should see a slight dribble from the bleed return, raise the revs to 1500-2000 rpm and it should 'wee' a steady stream.
With the engine off.. squeeze and hold the top hose, place a finger over the bleed return hole in the filler neck, release the top hose, remove finger. Repeat several times. See if the level drops in the expansion tank

This is what comes out of the bleed pipe with the engine running and when revving:


It starts with a steady spill when idling, then as I rev it seems to increase to a steady stream before stopping altogether.

Are you sure that the radiator is not blocked?

I am not sure, should I undo the drain plug and stick a hose in the top pipe?

 

[kermit_rr]

Are you sure that the radiator is not blocked?

It's possibly but it's not the same as the diesel radiator where flow can bypass the core

 

[kermit_rr]

It shouldn't stop. But that test is best with the pipe connected then you're not losing coolant.
Are you sure the pump is good?

 

[Datatek]

This is what comes out of the bleed pipe with the engine running and when revving:


It starts with a steady spill when idling, then as I rev it seems to increase to a steady stream before stopping altogether.


I am not sure, should I undo the drain plug and stick a hose in the top pipe?

as the radiator stays cool, I would certainly try flushing it with a hose. If anyone in the past has used one of the preparations to stop leaks, it may have partially blocked the fine tubes of the RAD.

 

[kermit_rr]

as the radiator stays cool, I would certainly try flushing it with a hose. If anyone in the past has used one of the preparations to stop leaks, it may have partially blocked the fine tubes of the RAD.

My biggest issue was a lump of silicone that intermittently blocked the bleed return hole.

 

[kermit_rr]

My biggest issue was a lump of silicone that intermittently blocked the bleed return hole.

Which 'could' actually be the case here as the flow stops in the video

 

[blue_cheese]

It shouldn't stop. But that test is best with the pipe connected then you're not losing coolant.
Are you sure the pump is good?

To the best of my knowledge, it was good before I stripped everything down

as the radiator stays cool, I would certainly try flushing it with a hose. If anyone in the past has used one of the preparations to stop leaks, it may have partially blocked the fine tubes of the RAD.

I will try this now.

 

[kermit_rr]

To the best of my knowledge, it was good before I stripped everything down


I will try this now.

What i did with mine, i took it off, laid it on the floor and poured boiling water into it as quick as i could, then felt across for cold spots. Have to be quick because the temp radiates very very quickly

 

[blue_cheese]

I broke my bucket

This is the flow out of the drain plug with the hose in the top pipe - I couldn't turn the pressure up very high because it would just blow back out the top.

Which 'could' actually be the case here as the flow stops in the video

I gave the bleed pipe a good blow from the rad side, and I could hear the bubbles in the expansion tank

 

[kermit_rr]

It should be gushing way more than that feeble drip. In my opinion

 

[blue_cheese]

Perhaps tomorrow I'll remove the rad completely and try and give it a good blasting.

Just tried it again after leaving it for a while.

Tried filling via radiator top hose, but it was already full. The metal pipe on the other end that goes to the block was also full.
Started it up, ran for a few minutes before coolant was being pushed out of the expansion tank.
Turned it off and put the cap back on, started it up again and ran for a few more minutes before starting to creep in to the red.


Coolant was coming out when the engine was warm.

I did notice a few things:
- Radiator was still quite cold, despite top hose being scalding hot.
- Top hose was quite hard, not rock hard but a bit stiff
- Inside the car, I could hear this odd noise:


Any ideas are welcome

Any ideas what this noise in the video could be? It might be a red herring, but I didn't hear it before the strip down

 

[kermit_rr]

Just tried it again after leaving it for a while.

Tried filling via radiator top hose, but it was already full. The metal pipe on the other end that goes to the block was also full.
Started it up, ran for a few minutes before coolant was being pushed out of the expansion tank.
Turned it off and put the cap back on, started it up again and ran for a few more minutes before starting to creep in to the red.


Coolant was coming out when the engine was warm.

I did notice a few things:
- Radiator was still quite cold, despite top hose being scalding hot.
- Top hose was quite hard, not rock hard but a bit stiff
- Inside the car, I could hear this odd noise:


Any ideas are welcome

This one? No clue