The V8 Owners Forum -

Make sure the new rad has a way of filling the rad itself. As on an SD1, etc.

need4speed wrote:Unlike my coolant, I feel like I'm going round in circles here...

So if it's not a radiator problem and it's not a waterpump problem, surely it's a stubborn airlock?

Edit: once I get new radiator in I will check the temp of the air coming out of heater. I don't believe my dad checked that..

Very possible yes.

IMO run the system with no pressure cap in place until you have confirmed water circulation.

Even maybe try and get some clear hose for a heater hose so you can get a visual that water is moving.

as said before we could do with some pics of your set up etc as we too are going around in circles lol,

may see something obvious in the pics,

Dave - it's an interesting point you make as the Audi rad we had didn't have a cap on it. Which I don't think helps at all. The radiator I'm looking at just now is for a 1.8TD fiesta. The inlet/outlet is on the same side which I need. It also has a cap on it

Stevie - I will be sure to run with no cap. If I can find some clear hose I will pick it up.

Tony- I will try and get some pics up once we have it all back together.

Thanks fellas.

need4speed wrote:Dave - it's an interesting point you make as the Audi rad we had didn't have a cap on it. Which I don't think helps at all. The radiator I'm looking at just now is for a 1.8TD fiesta. The inlet/outlet is on the same side which I need. It also has a cap on it

Stevie - I will be sure to run with no cap. If I can find some clear hose I will pick it up.

Tony- I will try and get some pics up once we have it all back together.

Thanks fellas.

Mate the cap is not meant to be on the rad its on the header tank so it does the same job,
the header tank fills the rad via the 19mm pipe on the left hand side of the rad,
the small 10mm pipe on the top right hand side of the rad goes back to the header tank which is the vent pipe to bleed any air back to the header tank,

which header tank you using????

You need to be careful if you've a cap on both the radiator and header tank, and also how any overflows or expansion bottles are plumbed with these as most caps allow water to be ejected when warm, then drawn back in when cool.

This can cause airlocks if the system isnt configured correctly with the right type of cap in the right place etc.

Really, it isnt difficult to get right, but it's also easy to get things wrong.

It's not a radiator cap on the SD1 it's a bung which is used as a filling aid.

http://www.gt40s.com/forum/gt40-tech-fu ... blems.html

Have a read at the above
Sure it is mainly Ford 302 but lots of impellers coming loose on shafts

Ian

ged wrote:It's not a radiator cap on the SD1 it's a bung which is used as a filling aid.

Yes - should have made that clear. It's not difficult to add one to a rad which doesn't have one if the tank is brass. Screwfix etc sell the bits for pennies.

Update.

New rad fitted. All put back together and carefully filled system with coolant. Ran engine for a few minutes and got a big belch of air. Topped up with more coolant.

Things seemed to be fine. Felt radiator and noticed now that it was same temp all over. Eureka I thought. Nope. Temp soon went through the roof again!

Borrowed a "sniffer" from a friend and checked coolant for hydrocarbons and................. There was none!

Trying to upload some pics but not having much success.

When mine had an air lock I had to drive mine for about 5 miles before it settled down completely.
When temp gauge went up what was the heater like?
If cold still it's an air lock.

When the temp went high, was the rad still hot all over?

Are you certain the gauge is accurate? There are lots of senders which look the same and fit the RV8. But you need the right one electrically for the specific gauge.

It's definately not the gauge as I've just learned this morning it pressurised so much it blew a hose off!

I just don't get it. I always thought if it was pressurising that bad it must either be a head gasket or slipped liner, but there would be evidence of hydrocarbons if that was the case?

Can't check heater temp as the motor needs replaced.

Pretty well all cooling systems are pressurized. Doing this raises the boiling point of the coolant. If it didn't build up pressure under normal running, it would mean a leak somewhere.

There is normally no pressure in the system when cold. It builds up as the system heats up and the coolant expands.

I've forgotten where we are - can you update us on your setup?

Chris.