Engine cooling, advice needed

[McDuff]

Hi,

 

Having started to use my Westie again this summer following an engine swap , I replaced a 1600 Ford CVH with a US built 1900 Ford CVH, and initially ran it with the bonnet off so I could spot coolant leaks quickly etc. I did not change the radiator.

After about 350 miles I put bonnet back on after completing the cut outs for the Webers .

I noticed quickly that the electric fan came on frequently during the drive, not just at junctions etc., but when the car was moving.

This does not happen with the bonnet off.

 

Prior to this the temp gauge was usually 3/4 the way across the gauge, sometimes running slightly cooler.

When the fan cuts in it goes to 1/2 way across,  as you would expect.

 

Clearly the fan should not come on when the vehicle is moving at normal speed. (The thermostat was newly fitted during the engine change)

. So how best to resolve it?

 

Should I adjust the thermostat on the fan so that it cuts in at a slightly higher temp?

 

I notice that there is some sort of homemade fibreglass ducting inside the nose cone which prevents air flow passing over and around the radiator, thus reducing/stopping some cooling air reaching the engine bay.  Should I remove this ducting?  (the fan is mounted in front of the radiator)

 

Will this reduce radiator cooling from the front?

 

Or, should I leave the ducting in place, and cut new air intakes in the top and sides of the nose cone/bonnet etc?

 

Any advice much appreciated, as always.

 

John

 

 

 

[Dave Eastwood (Gadgetman)]

Not sure if I'm following you completely, but I take it the ducting just stops any air from spelling past the rad, and forces it all through? There is no ducting behind the rad, ducting it out of the top of the nose cone or anything?

Much higher output/heat generating cars than yours should be have no issue at all with full ducting, where all the air coming through the rad exits the nose without going near the engine bay, so yours shouldn't be a problem.

Indeed, adding ducting in front of the rad, to make sure all air passes through it is the best way for the cooling system to run, once you've got above fifty/sixty mph.

If yours runs worse like this, then it suggest there's a problem with getting enough coolant round the system. It could be related to a dodgy thermostat, maybe not opening sufficiently, it could be related to a dodgy water pump, BUT first off, check the simple things - an air lock somewhere in the system is highly likely. Westfields of various descriptions, can occasionally be a pig to bleed thoroughly.

[McDuff]

Hi Dave,

 

Thanks for your advice.

 An air lock might be the problem since I have had a persistent coolant leak which will empty the expansion tank  over a few days , so I have had to refill several times, although this now seems to have been resolved, hopefully !

 

I believe the thermostat was recently replaced by the previous owner.

 

There is no ducting behind the radiator, The ducting that is fitted seems designed to force ALL  the air through the rad.  So removing the ducting might make matters worse ? Glad I didn't remove it !

 

Cheers.......John

[Dave Eastwood (Gadgetman)]

If it's running hot at speed with the bonnet on, then yes, removing the ducting will probably worsen the effect.

Air locks are typically the most likely issue, but don't rule out a faulty thermostat, even if brand new! Depending on the quality and age, it's certainly not unheard of to have out of the box failures!

Daft question maybe, but have you seen the engine run previously? Are you reasonably confident it's not brought a cooling issue along with it?

[Dave Eastwood (Gadgetman)]

Oh and daft question number two! Was it definitely a leak? I've have you seen water getting out, or evidence of a coolant leak, like staining on and around the location of the leak. Or have you just been seeing a falling level and topping back up?

Sometimes, an airlock, or more, a series of small air locks, can work their way round the system to the header tank, giving the impression of falling levels, over time.

[Robin Parker (Red Spider) - Yorkshire AO]

Come along to the meeting tonight, you can get plenty of advice there.

[McDuff]

Hi would love to attend, but have other commitment tonight.    Hope to be there next time though.

 

JW