related docs

MGF /TF Thermostat Modification 06.01.06 Rev 1

Some comments to the MG Cars BBS
1998 first suggestion to bypass the thermostat (Spencer, London)
1999 another speciallist discussion on the thermostat term
Copyright of MG Cars Enthusiasts' Club Limited,

From first experiance of Jon Fredheim one 2 to 4mm hole to the thermostat suround is enough. Lager or more holes block the engine in reaching the working temperatur !!!
Thermostat change. Instructions if the engine remains in the car (MGCars BBS)
From: Will Munns Cambridge 1600 midget without front bumper - and P Reg F on 05 January 2005 at 09:36:29 (UK time)
The thermostat housing(black) is hidden under the inlet manifold (which is black) in the darkness of the engine bay.
It has three 8mm head bolts (black) two of which are reasonably accessable and one of which is hidden round the back in a place that is almost impossible to get a ratchet on and only big enough to get about 3 degrees of movement on a spanner (which means for a box spanner, in one way, twist, out, turn over, twist, out ....)
Go to halfords and get yourself a 8mm ratchet spanner just for this bolt!

The thermostat housing has a metal pipe push fitted to it, it leads around the end of the engine and is bolted to the block in 3 (could be two) places with easily accessable 8mm headed bolts, undo these, now pull the whole assembly off the engine (only a little movement, try not to disturb any hose clips). Poke the thermostat out.
The new thermostat comes with a new gasket which sits on the thermostat, be careful when fitting that you do not pinch it, or it will weap and require a new gasket (and taking apart again (grrrrr).
You will have to do all of this blind as the inlet manifold gets in the way - does your digital camera have a webcam mode? if so could you get the PC close enough to see what you are doing using it?

  Kühlwasser ablassen... Drain the coolant
Rechts ganz unten liegt die Rohr Mischgruppe mit dem Thermostat.
Right downwards you find the coolant mix pipe with the thermostat. Most difficult to get it of
Use a flex driver !!
So leicht wäre es bei demontiertem Motor.
Ansicht aus Richtung Ausgleichsbehälter
It would be easy at a disassemled engine.
View from direction coolant expansion tank
Ansicht des Motors von hinten.
Der Thermostatflansch steckt normalerweise in der angezeigten Bohrung
View from the rear side to the engine. Normally the flange of the thermostat sticks in the indicated hole.
Die Rohrgruppe aus einem Wrack.
Rechts aussen das Motor Entlüftungsventil
The pipes with the thermostat attached to the right side
(engine bleed valve on the left)
drei 10er Schrauben, die sehr schwer zugänglich sind.
three screws with 10mm. Hard to access.
Einblick in das Thermostatgehäuse.
View to the thermostat case.
Drei Schrauben herausdrehen. Der Thermostat sitzt fest mit einer Gummieinfassung im Gehäuse
Unbolt three screws. The thermostat is surrounded by a rubber sealing.
Vorsichtig herausziehen
Pull it out carefully
- Dichtung entfernen
- 1 Bohrung max 4mm anzeichnen
- Remove the sealing.
- Marka hole to be drilled in maximum of 4mm
Nur ein Loch, 2 bis 4 mm bohren
drill one hole only, app 2 to 4mm
Sauber entgraten
make the surface flush and clean from metal spans.
  Sauber abwaschen und Dichtung wieder montieren Wash it under water and refit the sealing.
Fertig zur Montage

Version mit einem Loch
Ready to get re-mount

1 hole version

Nun 'einfach' in umgekehrter Reihenfolge wieder einbauen. Nur die Löcher nicht noch einmal bohren.

Und dann schön die richtige Kühlwassermischung auffüllen und peinlichst entlüften..

Just follow this instruction backwards ... without drilling the holes again ;)

Refill the system with coolant mixture and bleed the carefully:)
Temperature Option

Ein weiterer Vorschlag, bereits von Carl erprobt:
Den 88°C Standard Thermostat gegen einen kühleren austauschen.

82°C Thermostat

  A second option:
Already tested by Carl is the mod to a cooler Thermostat. He changed the Standard 88°C to a cooler 82°C Thermostat


Reworked Thermostat. Outer diameter made smaller to meet the right diameter and drilled 2mm hole.
picture courtesy Jon Fredheim

Dimensions for a 82° replacement.
Tested products:
- QTH100 from QH, (myself)
- 'Tridon 8620 7882' (Jon F.)

both to file down to 50mm outer diameter.

By Ian suggested product:
The maestro/montego thermostat has the "jiggle valve" that carl was talking about and are interchangable with the metro so will probably fit the MGF.
The part numbers are GTS106 for the 88 degree one and GTS104 for the 82 degree one.
These are the Rover part numbers.

Simon has another modification developed for his Elise.
Carl has already worked out something for the MGF.

Remote Thermostat options page 31.12.01 with what Carl did

And now official at MGR see at Carlos

The same from RED (I think) to be installed as short circuit in the engine bay (Pictures courtesy Thierry Zoller)

PEL000040A - Flange-water pump outlet (PRT related)

New design Thermostat ???
I got this nice part from a guy who supplied to the german Elise community. No idea where he got them. The outer diameter just fits to the MGF Thermostat housing with 50mm diameter. Notice the seal groove. The original rubber gasket is still required though.
It's a 82° C thermostat.

See the jiggle valve included. It allows air in the system to get back in direktion coolant expansion tank. (Mount this thermostat into the housing with the valve on top to allow air bubbles flow back to the expansion tank)

rear viewfront view 

However. The MGTF has got another system. Look at Rob's site for detailed descriptions.

PRT (Pressure Relief Thermostat on MGTF sinc MY 2004 (app.)
Parts required listed in the EPC under
Pipes and Hoses & Thermostat

Another image of #8 assembly and #13 assembly courtesy Dave Livingstone UK
old design on the left, new with PRT on the right.
click for larger image

Interesting stuff at Carlos Elise Site

News 2007 at Lotus Elise forum

PRT Colours :
- Cream is 88° With hard Spring [Designed for Diesel and V8 applications]
- Black is 82° With Hard Spring (Designed for a V8 and used as a stopgap with K4 engines)
- Grey is 82° With Light Spring

So perhaps the N series has the Landrover MLS gasket, oil rail and grey thermostat.

For those with PRTs fitted its PEL500110 £8.75 grey PRT from Rimmer Bros. (may be )

The latest on the matter at wikipedia

back or to my MGF home site

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