Topic

A couple of week ago i purchased an F which was advertised as head gasket blown. Intention was to use it for spares for my F and TF. Having examined it and done a few tests it appears not to have a blown head gasket. Last week i could hear the fan running when i switched the engine off after running up to operating temperature. This week when trying to get it up to temperature ( to run an engine compression test ) it won't fully reach operating temperature the fan doesn't come on and the coolant is constantly circulating. I'm thinking thermostat issue. Am i missing anything else ?

I presume you mean constantly circulating by looking in the expansion tank Y/N?, if yes it could be the jiggle valve is stuck or has been disabled by a PO. The valve is there to enable any trapped air to vent via the expansion tank but normally not water, a stuck or disabled valve will allow water to flow conatantly thru the small pipe on the side of the expansion tank and show as agitation in the tank. There are lots of threads on the jiggle valves some say they are needed some say not, personally I err on the side of caution MGR did not spend enough on R & D but they still spent a lot and most things are there for a reason.
I'm only into my 3rd year of TF ownership so not an expert but my experience so far is some people will diagnose a flat tyre as a HG failure, I would be very interested to know the results of your compression test as HGF is it seems always the 1st port of call.
Good luck hopefully you'll end up with an engine as a spare or one you can pass on.

Hi deepfat thanks for the reply. The coolant constantly flows from the small pipe at the side of the expansion tank. I'll investigate the jiggle valve once i find out what and where it is. As for the compression test the first results were all over the place but i hadn't done one before so i did them again ( hopefully correctly this time ) they came back as 175 on 2 and 177 on the other 2. I had also done 3 chemical tests over the last week and all came back negative. This morning I removed the thermostat housing and changed the thermostat. There was a small leak from the housing so it wasn't a wasted morning. I had done a compression test on the expansion tank, over a 6 hour period the psi had dropped just under 2. Hopefully the small leak explains that.

Those compression figs look good to me, so carry on checking thru the cooling system and you should be good to go, will you still break it or sell complete? SPQR but then no bank of spares decisions decisions.
Re the jiggle valve this might help http://www.mgfcar.de/bleed/ scroll down it's comes after the bit about bleeding and has a piture showing location click on it and its position is clear.
I've also attached a schematic (I presume correct) of the F cooling system which might help it shows 2 jiggle valves that both vent to the expansion tank so 1 or maybe both could be the problem. As stated before read up on the threads but it's awkward as most people (like me) do not fully understand the cooling system, hence it must be the HG.

Thanks for that information. As for the car I'll leave that decision until I've finshed with the cooling system. Although truth be told that decision might not be mine. Having 3 mg's sitting in my driveway hasn't gone unnoticed by my other half.

Just remember to return the favour and notice yet another pair of shoes 👠 that she may be sporting.

We are currently moving house, last time we moved, I took a full Ute (pickup) load of shoes in their boxes, to this house.
Oh course I remarked on it at the time and have brought the subject up at every opportunity.
This time I’ve noticed the shoes are trying to fly under the radar by going across to the new place in dribs and drabs.

Hi Cobber
I just have to mention Sewing Room and she gets defensive 😂😂😂

I don't see what the problem is,it's only 3. And my daily can still fit in at the top of the driveway 🙄