Coolant replacement and removing air from engine

[interceptor@joc.org.uk]

Hi all,

I have seen many YouTube videos recently which use a vacuum to fill engine/radiator with coolant. This means that the coolant passages are all evacuated of air first and then coolant is pushed in under vacuum ensuring that once the coolant is topped up, there is no air and 100% coolant in the system.

Has anyone tried this on an Interceptor V8 or similar and is it possible. I would love to know where to get the kit to do this as I already have an air compressor in my garage.

Lastly, I am sure this will benefit coolant replacement successfully.

cheers
Neil

[Grant]

Neil, I'll be perfectly honest and tell you that I have never suffered with air-locks in the cooling system in Interceptors in all the years I've been mucking around with them, So save your money from that device and put it on Black Beauty @ 2.00pm at Ascot...You never know you may win.. It happened to me you know, I had a big win on the lottery, I came home and said to Lara..Quick Quick..Pack your bags I've won the lottery, she said "What shall I pack Something heavy/Something Light?".. "Just pack your bags and Bog Off out of it" I said

[slotcarone]

Like Grant said that is not necessary on an Interceptor. I have found that is you leave the expansion tank half full and fill the radiator up to the top that the car will cool fine. You have to do it cold and take the cap off and slowly add coolant right up to the bottom of the cap neck. Then leave the cap off and wait about ten minutes and go back and fill again. Repeat until there is no more room for coolant and then put the cap on.

[interceptor@joc.org.uk]

This is interesting, as I recently rebuilt the cooling on a Mk3 and filled it up, then kept topping it up until all was full.

But, the Expansion tank cracked on initial running..

Then, after fitting another expansion tank - used - from a Jensen supplier, this cracked as well...

3rd time lucky, the new expansion tank is okay but with a 13psi cap it started to leak

Now 15psi cap is on its way. But on a 10 mile test drive with the radiator filled slowly and carefully, the coolant decided to end up on the floor via the expansion tank which I could only believe was due to air in the system. The fans were on override so non stop after engine switched off and coolant still made a good mess of the floow.

Hence I thought, maybe still air exists somewhere.

I would love to win anything, but better still, I would love to be able to stop Interceptors from overheating....

cheers
Neil

[Steve Payne]

Neil
It sounds like you might have another problem.
What temp do your cooling fans cut in at and what temp is your engine after a 30 min run. Not what is says on the gauge what the actual temp is at the top hose where it leaves the thermostat housing.( Infra red thermometer is useful A lot of gauges have been slugged to read normal.
Have you removed the cylinder heads? The passage ways in the head gaskets could be blocked or they could be the smaller slits in the gaskets that need opening up.
What thermostat do you have fitted and is it opening correctly?
What cooling fans do you have? I have seen some of the uprated ones supplied by the recognised suppliers little better than the ones fitted originally. A couple of 200 to 250watt fans should work but I have seen some recently that were only 75 watts each. The bigger fans will also need a good power supply so a Mitsubishi Alternator is a good idea so they are spinning at there optimum speed.
Steve

[RockyUSA]

Cracking your expansion tank means you have too much pressure, I don’t think a higher PSI cap is going to solve your problem…

I agree with Mike, see what else you can find in your system that may be causing the problems!

Rocky

[Grant]

Something doesn't sound right here Neil with it splitting your expansion tank,, any over spill if the system is too full should find its way passed your 13psi cap that should always be fitting to the expansion tank,(the non bypass cap should never be fitted to the expansion tank) . Even if your system is being pressurised maybe due to faulty head gasket blowing into the water ways it should really push passed the 13psi cap still I would have thought, sound's like it needs further investigation there Neil
P.S, make sure your heater matrix valve is working and open when filling the system, the matrix heater valves do tend to seize in these cars as they normally sit around for years and they seize, you can always bypass it as a temp measure it by using a piece of tube if it is seized closed

[DPP]

Jensens only overheat because of problems within the system and as mentioned even after replacing the radiator and upgrading fans, if there is a blockage in the engine it will still overheat.

Most engines I strip down have the coolant passages in the head gaskets blocked by years of debris in the system and when rebuilding and engine I remove all the core plugs and use a steam cleaner at 150 degrees c to clean out all the water ways on an engine and you would be surprised how long it takes for clear water to come out so just flushing with a hosepipe will help but will never remove 50 years of accumulated dirt.

Ive even found old core plugs inside cylinder heads so unless you fully strip and inspect something you will never be sure its working at its best.

[Grant]

I agree with Mark,
Rocky

Who's Mark then ChuckyMan..Was he someone who just popped around your house and gave you his opinion?

[RockyUSA]

Maybe it’s SC1, or maybe it’s just someone who popped around to my house, and suggested the answer…

My mind is getting foggy in my advanced age!

Chuckyman!

[jvcarrier]

Make sure the fans are blowing the right way.

[Grant]

Make sure the fans are blowing the right way.

Which is pulling air from the grill to inside the Engine Bay Neil

Maybe it’s SC1, Chuckyman!

Ahh Mike you Mean ChuckyMan