Coolant thermostat apperture?

[MINESAPINT]

Hi Guys,

Could someone shed some light on my overheating problem.
400 SE. Car runs fine on Motorway for about an Hour, then the temp rises right to the top just before the red. Had a recore done on radiator last year. Taken out the thermostat (74 degree) and checked in hot water. The stat opens but only seems to go half way down. Is this normal or should it open more fully?

I'm thinking that if it is restricting the coolant flow then the system is not effective enough?

Or could it be the water pump impeller?

I would appreciate your comments on this one guys n (gals), sorry that sounded abit
Jimmy Savillish ooops.

[keatsie]

It's always difficult with cooling, if the thermostat is opening and you have had a recore, and assuming you flushed the engine through it is more likely to be a blown head gasket than the water pump.

Your going to have to check to see if he radiator is warming across the core, this will let you know if the pump is functioning, replace the thermostat as a matter of course, being only a couple of pound it's worth a go.

Are you loosin any coolant, is the over flow getting coolant pushed in and is the radiator fan cutting in?

[MINESAPINT]

Cheers Keatsie,

I have checked oil (no water), checked water (no oil), system is not blowing coolant out, although there is pressure there (less than 16lb, thinks this is normal)?d

The fan is coming in and the exspansion tank is getting warm.
Not checked radiator core temp.

Will replace stat and check water pump impeller as a matter of course.

Edited by MINESAPINT on Monday 13th May 14:04

[honestjohntoo]

The most likely cause of your problem is that you have a combination of a possible leak plus air locks in the cooling system, notwithstanding that you have no blockages anywhere that can be resolved by flushing and reverse flushing

As a result, when a pocket of air is trapped at the hottest locations (ie: exhaust manifold area water jackets), the coolant thereabouts immediately turns to superheated steam which then finds its way to the coolant gauge sensor on the inlet manifold before the steam condenses back to coolant.

That superheated steam is what gives you the frightening rise in measured temperature.

I have written two definitive articles on these and other RV8 coolant phenomenons and resolutions,

There is also another essay on how I get the air from my own RV8 cooling system.

Much of this may apply to your engine too!

If you wish to study them go here:

http://www.vintagemodelairplane.com/pages/Rover_Te...

http://www.vintagemodelairplane.com/pages/Snippets...

http://www.vintagemodelairplane.com/pages/TipsAndT...

Whatever? Good Luck!

[ElvisWedgely]

Does the car actually overheat? or is the gauge just showing near red? I have owned several V8 wedges and they all run pretty hot and very close to the red mark on the gauge, especially in traffic. You may not have a problem at all, as long as the water is not being pushed out and the water and oil are not mixing and there is no mayonnaise inside the oil cap, and the fan kicks in, there shouldn't be a problem. Just make sure there is pressure in the cooling system and that you have the correct 15 Lbs cap that makes a good seal. It's the pressure that maintains the cooling within the system.

Tony. TCB.

[Danny Hoffman]

Are your fans running in the correct direction?

[MINESAPINT]

Great feed back brothers,
Danny great point as I replaced the radiator myself and it is a possibility that I have connected the plug wrongly. Also I only have a single fan which seemed to do the job before.

Honestjohntoo - those articles are very informative and will look to check and refill system as suggested. The car did run close to the red before I fitted a 74 degree thermostat which seemed to keep the temp central on the gauge (4 years ago), now with the same thermo in it runs very close to the red. That's why I checked it in the first place.

Tony the pressure caps on the expansion tank and inline metal pipe are quite old so will replace both with 15lb new ones.

Thanks guys for your time and thoughts.

Edited by MINESAPINT on Monday 13th May 19:03

[B@man]

Hi Just a small point but the cap on the swan neck should be a non pressure cap and the one on the expansion tank should be the 15lb one. Mate of mine with a 350i had them the wrong way round and had loads of overheating problems until he swapped them over.

[MINESAPINT]

B@tman, that's a good spot too mate, done that before, put a 15lb one on the filler tube as well as the exspansion tank (did not realise it would make a difference).

Edited by MINESAPINT on Monday 13th May 19:40

[jepebe]

Looks like the same problem that I experienced with my 350i. No problems after a longer period of non use, but then after one hour the gauge went to 100-110, and down again. It then started to appear after shorter periods of driving, say every 10 minutes or so. I flushed the system, replaced the thermostat (74 in stead of 82 which was installed) and...good steady temperature. So maybe you should just replace the thermostat, it may be the source of your problems.
And..apologize for the language, not all the Dutch do write well.

[adam quantrill]

Is that - dare I say it - Double Dutch???




I'll get me coat.....

[jepebe]

That happens when you don ' t post too often...and take an umbrella with you...

[jon haines]

Having had similar problems recently i was adviced by a guy who has a lot of experience with rv8 engines that it was an air lock and that the complicated tvr plumbing meant that some of the coolant pipes from the expansion tank to engine then swan neck were too low and that was the problem. he advised me to re route some of the pipes but to lift them up higher. did as advised and hey presto problem solved. i have also had my head gaskets done last year, new rad, new thermostat so its worth a go.

[MINESAPINT]

Hummm, I do have the coolant pipes to the exspansion tank under the swan neck. Will flush and refill move the pipes higher check the rad caps are correct, burp the system and see how we go.

Wish me luck!!!!!!!!