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MG MGF Technical - PRT thermostat

Hi all,

I am trying to get a MG TF pressure sentive thermostat installed on by MGF (rather than an aftermarkre remote thermostat).
I have found a drawing on
http://www.mgf.ultimatemg.com

I have not been able to find more info about what parts are exacly required, like hoses and stuff. I have been trying to compare the drawing with the original one from the workshop manual, but it just doesn't make any sense to me.

Is there anyone who has done this conversion, or knows a internet site which explaines this some more.

Thanks
A.P. van Wijngaarden

Marco's Elise site has fitting instructions. I don't have the URL here, but I'll find this out for you tomorrow :o)
Rob Bell

Here's the page you need: http://web.tiscali.it/elise_s1/index.htm

Landrover parts for the remote stat can also be used - although they are slightly different. I am still not 100% clear on what all those differences are though!
Rob Bell

Hi A.P.

Here is a picture of the old and new hoses compared side by side.

http://www.mgs-on-track.com//images/uploads/PCH002960_Top_Hose_assembly__PCH002970_Bottom_Hose_assemb1.JPG

The new PRT is the white plastic thing in the hose assembly on the right. The hose assembly on the left is the original MGF for comparison. I've had the new PRT successfully retrofitted to my '98 VVC by Techspeed Motorsport. The part numbers are:

PCH002960 – Top Hose assembly
PCH002970 – Bottom Hose assembly
PCH002790 – Heater Bypass assembly

I have an article that I wrote for Safety Fast magazine which I can send you. It doesn't have technical detail, but does mention a few things that might be helpful. Just email me for a copy.

HTH
Dave Livingstone

Thanks all,

Rob, do you know if the Lotus Elise configuration is the same as the MGF? Because the picture on the link is different than the picture in Dave's link?

Dave: I have sent you an e-mail. Thanks for the part numbers, I'd better start asking for some prices at my MG-Rover dealer. I have a question though:
Is it nessecary to replace the Top Hose assembly? Becasue on Rob's link there is no reference to this and the picture you've sent, also only shows the Bottom Hose and Heater Bypass assembly.

Greetings,

Alex
A.P. van Wijngaarden

Alex, fundamentally the two systems are the same, but there are differences to the pipe work as the heater and under body coolant pipes are located differently between the two cars.

If you are able to source a TF kit, then clearly, the whole thing is a good deal more straightforward, as it is more a case of remove old, and replace with new (with a bit of fiddling with the heater hoses IIRC) - whereas with the Elise, there is going to be a fair bit of 'bodging about' to get the fit.
Rob Bell

I have bought the 3 hose assemblies of the TF and the thermostat. Now I'll have to wait for the expansion-tank with the level sensor to arrive and I can start replacing!
A.P. van Wijngaarden

Hi all,

I'd like to bore you all with some other questions about the PRT.

Currently I am trying to find out how to connect the hoses the right way.
I have found a nice drawing of the hose assembles:

http://www.mgf.ultimatemg.com/group2/common_problems/hgf_pages/HGF_images/TF_PRT_circuit_complete.jpg


Using this drawing I have been able to figure out how to assemble and connect the top hose assembly snd the bottom hose assembly. Please correct me if I am wrong:

Number 9 on the drawing connects to the large diamter engine coolant outlet(where the temperature sensors are located)
Number 11 outputs the hot water to the radiator underfloor pipes.
Number 20 receives cold water from the radiator underfloor pipes.
Number 14 connects to large diameter tube of the coolant rail and is the engine coolant inlet.
Number 16 is connected to the heater underfloor pipe and receives the returned coolant from the heater.

For the heater/bypass I am not able to figure out how these should be connected. I assume that:

number 4 is connected to the heater underfloor pipe, that feeds the heater.
number 5 is connected to the small diameter engine coolant outlet (where the temperature sensors are located)
number 3 is connected to small diameter tube of the coolant rail. (instead of the weird bended assembly with the joggle valve)
number 2 is connected to the side of the expansion tank.

When I am correct about the fitting of the heater/bypass hose assembly, there will always be a bypass present, from the small diameter engine outlet to the small diameter engine rail, because the original thermostat will not close the bypass. Is this correct?
Also, what will happen to the jiggle valve, which in the original setup prevents pressure buildup in the expansion tank?
Finally, the original bleed line had two connections, one at the jiggle valve and one at the engine (although I do not know where).When connecting number 2 to the expansion tank, the engine bleed connection can't be connected anymore...

It's getting quite confusing for me now, so any help would be appreciated.

Alex
A.P. van Wijngaarden

>>When I am correct about the fitting of the heater/bypass hose assembly, there will always be a bypass present, from the small diameter engine outlet to the small diameter engine rail, because the original thermostat will not close the bypass. Is this correct?<<
yes, you need this flow for the temp senders.
>>what will happen to the jiggle valve, which in the original setup prevents pressure buildup in the expansion tank?<<
According to Dave Livingstone's TF upgrade it should be discarded (I kept it on the Elise setup). The valve is there just to give a quicker coolant warm up, excluding the coolant in the reservoir from the flow.
>>Finally, the original bleed line had two connections, one at the jiggle valve and one at the engine (although I do not know where).When connecting number 2 to the expansion tank, the engine bleed connection can't be connected anymore...<<
I suppose you can use the original bleed hose instead of #2, keeping the inlet manifold bleeding point.
HTH
Carlo
Carlo

>what will happen to the jiggle valve, which in the
>original setup prevents pressure buildup in the
>expansion tank?

Errm not read this thread, but the jiggle valve is only there to allow trapped air a way of getting to the expansion tank, whist limiting the flow of water thru the same path - nowt to do with pressure buildup
Will Munns

I would like to keep the jiggle valve. But I am not sure how. Should I just cut a bit of the #2, which I won't be using then, and connect the jiggle valve to the 4-way connector, #7 in the drawing?
A.P. van Wijngaarden

>>I would like to keep the jiggle valve<<
I suppose you mean the one close to the temp sensors (the inlet manifold bleeding point has also a jiggle valve).
On the Elise it is easily achievable because the heater circuit is different, I'm not so sure about the MGF/TF (the PRT setup on the newer MG-TF uses a completely different heater setup compared to the older MGF).
This said and with a big disclaimer, you can use the old circuit to feed the heater, swapping around the two heater hoses, using the old bypass instead of #4 as heater inlet (originally it is used as heater outlet) and #16 as new heater outlet.
I have some doubts about the heater functionality with this setup: a close look at the 4-way connector internals could be of some help (I suspect there is some restriction between #5 and #3... the same restriction should be fitted to the old hose)

Cheers
Carlo
Carlo

This thread is starting to sound like the Ikea instruction manual from Hell...

Any chance of some illustrations for simpletons like me?
Rob Bell

>This thread is starting to sound like the Ikea instruction manual from Hell...

You mean like an Ikea instruction manual from Ikea?

Argh, I'm getting annoyed just thinking of that god forsaken hole.

Excuse me for a few minutes
Will Munns

This thread was discussed between 19/05/2005 and 26/05/2005

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