Lots of steam

[SD1too]

Originally Posted by FLYING BANANA

I put the old radiator cap back on it has stopped the steaming.

The old radiator cap is probably perfectly ok then (as demonstrated earlier when there was no change to the unstable coolant temperature). Why did you change it originally?

We are still getting some coolant loss, checked this morning and it had definitely gone down as the lower level indicator was dry.

If you can't see coolant or antifreeze residue or steam anywhere then it may not be continuing loss but an air lock as TourerSteve says, or an unsealed system as I have suggested.

I would drain, refill and bleed the system before paying for a pressure test or speculatively renewing the PRT. That will confirm or rule out an air lock at minimal expense.

Thanks for the updates Bob, please keep them coming.

Simon

[FLYING BANANA]

Originally Posted by SD1too

The old radiator cap is probably perfectly ok then (as demonstrated earlier when there was no change to the unstable coolant temperature). Why did you change it originally?


If you can't see coolant or antifreeze residue or steam anywhere then it may not be continuing loss but an air lock as TourerSteve says, or an unsealed system as I have suggested.

I would drain, refill and bleed the system before paying for a pressure test or speculatively renewing the PRT. That will confirm or rule out an air lock at minimal expense.

Thanks for the updates Bob, please keep them coming.

Simon

The cap was changed when the new radiator was fitted back in February this year. The cap arrived about 3 weeks after the radiator was replaced. No problems till last weekend when the steam “incident” appeared.

I don’t have the facilities to drain, refill or bleed the system. My only option is to get the car up to Matt’s, a 40 mile run, or book the car into a local garage to have the work done.

Banana is at the top of the list to get repaired. As the SMART car is in the workshop, I’m having to rely on the V8 to get me about.

But thanks to everyone for all the tips and ideas to get ole Yella sorted out.

[FLYING BANANA]

Since the radiator cap “incident” I have debating whether to use Banana on a long run.

So today we done a 193 mile round trip to Sparkford in Somerset and back home to Saltash in Cornwall. She ran perfectly sweet. The onboard diagnostic read between 81-88 degrees.

[SD1too]

Originally Posted by FLYING BANANA

So today we done a 193 mile round trip to Sparkford in Somerset and back home to Saltash in Cornwall ... The onboard diagnostic read between 81-88 degrees.

Thanks for this latest news Bob.

The ambient temperature today was below 10˚C which, according to my analysis and the type of journey you made, explains your low but safe running temperature. I'm sorry to say that I don't believe that the overheating problem has resolved itself.

Simon

[mbonwick]

Originally Posted by SD1too

I'm sorry to say that I don't believe that the overheating problem has resolved itself.

Simon

Careful there Simon, Bob does not have an overheating problem.
He potentially still has a coolant loss issue (though personally I believe it has been solved - subject to the coolant still being at level in the morning), but at no point has the car showed even the slightest tendency towards overheating.

[FLYING BANANA]

Originally Posted by mbonwick

Careful there Simon, Bob does not have an overheating problem.
He potentially still has a coolant loss issue (though personally I believe it has been solved - subject to the coolant still being at level in the morning), but at no point has the car showed even the slightest tendency towards overheating.

By the time I got back today, and in desperate need of a wee, I didn’t check the coolant level. But I will do first thing tomorrow.

As correctly stated the car has not overheated, just lots of steam initially.
But with the change of the cap we no longer have any steam. As for the diagnostic check on the temperature, at a constant speed of 65 mph it stayed level at 84 degrees. Never went up or down. Going down hill it dropped to 81 and on climbing up the hills it rose to 88. Only once did it reach 90 degrees, and that was when I pulled up at home and manoeuvred into her parking space.

I’m getting the coolant pressure check tomorrow. After I book the Bear into the garage. She needs other work, so I might as well get it all done at the same time.

[bl52krz]

Hi Bob. Just a thought. I noticed many years ago, my car was parked up for around three days, and the weather was very damp and misty, and when it was started, after a few minutes, steam started to come from the radiator. It came from the honeycomb of the rad not the pipes or the header tank. I thought there was a water leak. This was only an observation, that could have been mistaken for water leaking from the system.

[FLYING BANANA]

Originally Posted by bl52krz

Hi Bob. Just a thought. I noticed many years ago, my car was parked up for around three days, and the weather was very damp and misty, and when it was started, after a few minutes, steam started to come from the radiator. It came from the honeycomb of the rad not the pipes or the header tank. I thought there was a water leak. This was only an observation, that could have been mistaken for water leaking from the system.

I have had that in the past but on this occasion the steam was coming out of around the cap and out of the overflow pipe.

[SD1too]

Originally Posted by mbonwick

Careful there Simon, Bob does not have an overheating problem.

Thanks for this Michael. Having reviewed the whole thread I can see that Bob reported that the steam coming from the overflow pipe and expansion tank cap has stopped after refitting the original cap. So I agree that without steam I no longer suspect overheating.

Originally Posted by FLYING BANANA

But with the change of the cap we no longer have any steam. As for the diagnostic check ... at a constant speed of 65 mph it stayed level at 84 degrees. Going down hill it dropped to 81 and on climbing up the hills it rose to 88. Only once did it reach 90 degrees, and that was when I pulled up at home and manoeuvred into her parking space.

Thanks for the latest data Bob. I look forward to hearing whether the coolant loss has stopped following the change of expansion tank cap.

For an engine with a conventional thermostat, the temperature should be reasonably stable when the car is moving, whether it is coasting downhill or climbing a gradient. A variation of 7˚ is excessive. However, you have a PRT which is more complex in operation. From reading T-Cut's detailed investigation into these I understand that the original colour coding (indicating opening temperature) can no longer be relied upon. Therefore we probably don't know which variation your car has which would make drawing a conclusion from the temperature readings difficult.

Simon

[FLYING BANANA]

Checked the coolant this morning and no further loss.

Took her for another run this morning and the temperature was between 81-88. So it seems to stable.

Many thanks to all for the advice and tips.

Makes me proud to be a member of this Great club.