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        General >> Problems >> Overheating - recent Radweld application
        
(Message started by: Mike_Floutier on Aug 12^th, 2008, 7:27pm)

Title: Overheating - recent Radweld application
Post by Mike_Floutier on Aug 12^th, 2008, 7:27pm

I blew out my radiator on Friday (looks like this http://www.exhortations.co.uk/images/PICT0038.jpg) , I thought it may have been caused by cylinder head problems but this turned out not to be.

The only symptom I now recognise prior to the blowout was the fact that the coolant fans kept coming on when they shouldn't be. When I ran the car today, after the replacement of the rad. the fans came on again when the engine was only just warmed up.

Because I've very recently put in a bottle of Radweld (not the first) I'm guessing there may be a link. I also guess that I need to reverse flush the cooling system (something I've never done and something that's never been done to the car in 314,000 miles.)

PLEASE can you tell me how to do it - AND if there's anything else I should be doing.

Thanks

Mike

Title: Re: Overheating - recent Radweld application
Post by bizzay1 on Aug 12^th, 2008, 10:42pm

Why did you put the radweld in in the first place Mike ??

Title: Re: Overheating - recent Radweld application
Post by Mike_Floutier on Aug 12^th, 2008, 10:52pm

I have a couple of leaks that I couldn't stop. One is in the body of my lpg vaporiser and the other is around the thermostat housing. Earlier today I noticed that both of the sensors in the stat housing could be tightened considerably and there was evidence of leakage around one of them.

Notwithstanding this I DO NEED to learn how to reverse flush the system to try and get rid of any blockage cos I'm supposed to be back at work (driving the Scorp) at lunchtime tomorrow.

Mike

Title: Re: Overheating - recent Radweld application
Post by bizzay1 on Aug 12^th, 2008, 11:10pm

I have never done it Mike but, all I would suggest is flushing the heater matrix - remove both heater hoses from where they go through the bulkhead and flush through with a hose first one way then the other, not sure you would be able to do it through the engine unless the thermostat were removed, as it would be closed and cause a restriction anyway - sorry I can't be of more help

Title: Re: Overheating - recent Radweld application
Post by Tompion on Aug 13^th, 2008, 1:12am

Mike

When you say “fans came on again when the engine was only just warmed up.”
How hot were the sensors?

When I took a reading via OBD the fan came on at 210F (with the aircon off).

So if the ECT sensor itself doesn’t feel that hot you may have a faulty sensor/fan etc.

What I'm saying in effect is it doesn't matter how hot the engine is it's how hot the sensor is (or thinks it is) as that's what the engine management goes by.

When the stat is closed water just goes through the heater matrix, as the stat opens it goes through the rad as well. A faulty stat is a possibility, you could try taking it out as a temporary measure.

You also need the right amount of antifreeze in as it raises the boiling point.

Be careful tightening the sensors as they are a tapered thread – they don’t go all the way to the shoulder.

Dave

Title: Re: Overheating - recent Radweld application
Post by Mike_Floutier on Aug 13^th, 2008, 5:40am

Thanks Dave,

The thermostat is very old so I'll get another today. I suppose if it was stuck closed the temp would soar and with it the pressure - and although the FLOW is kept away from the rad. the PRESSURE is not.

I suspect the sensor is ok because the unusual fan activity coincided with the rad. blowout.

I'll do the flushing while Mrs F. gets the stat. I'll try and get new sensors as well; the guage sensor is faulty anyway.

Thanks

Mike

Title: Re: Overheating - recent Radweld application
Post by Mike_Floutier on Aug 13^th, 2008, 10:39pm

Just to confirm that the flushing went fine in both directions everywhere. New stat and both new sensors all ridiculously cheap. Nearly new radiator from Nottingham Ford dismantlers £32 inc vat & postage. Ordered Monday arrived Tuesday. They have been great for parts - via Partsgateway.

All works like a dream!

THanks

Mike

Title: Re: Overheating - recent Radweld application
Post by amigafan2003 on Aug 14^th, 2008, 11:19am

Also, remember that the fans come on with the air conditioning as well - the airflow is needed to cool the condenser rad in front of the coolant rad.

In fact, on a warm day it's common for the fans to be on as soon as the car is started.

Title: Re: Overheating - recent Radweld application
Post by Mike_Floutier on Aug 14^th, 2008, 2:03pm

Thanks Amigafan2003!