Thermostat housing

[SimonR]

Hopefully soneone's experienced this and can help me make my heater work again, if this is what's causing it!

F153's original engine configuration had an old-type expansion tank (small inlet hose on righthand side) with a long narrow-guage hose running from that to the top of the thermostat housing. It also had a one-piece top hose to the radiator.

During all the work I did to it, I changed the expansion tank to a later design, replaced the top hose with the latest spec (now it's a large hose with the small hose comming out of the top) and blocked up the hole at the top of the thermostat housing.

I reckon that this is causing my engine not to get upto the correct working temperature, because now it looks like the thermostat has no effect and water is always going through the radiator, even when the engine is cold. Thus my heater doesn't work because the engine never gets hot :(

Are my assumptions correct? - or is my thermostat just not working?

If I need to replace the thermostat housing to the latest spec would a Maestro *or* monty one do, or are they different? although I've not seen the later design I can't work out how the thermostat works because how can it stip water gping through the radiator if the return hose is part of the radiator hose... ?!

Thanks!

[talkingcars]

IIRC there is a small bypass hole in the thermostat to allow some water through in case of it failing, however the first thing I would check is the thermostat itsself. The old test of putting it in hot water to watch it open and cold water to watch it close. With your perticular problem I would also be tempted to run for a couple of days with the termostat out to see if the car behaves the same.

James

[E_T_V]

Take the thermostat out when the engine is cold. if it is open it is knackered. Get a new one. If you can get an 88°C (the standard one is 82 I think) one as this'll make the heater work better. It might be that all the work you've done has dislodged some rust that is now stopping the thermostat from closing. Get it swapped, they are less than a fiver and you'll know for sure that is is an ok one.

[SimonR]

Thanks for those replies, chaps.


I think you could be right although I did change the thermostat a couple of years ago. I guess that may be long enough for it to be nackered now.

I think an 88 degree one might not be such a bad idea although I can't see how it works in the new configuration thermostat housing!

It's off to Rover on Saturday morning I think, MaestroMatt is going anyway so I'll hitch a lift in A82...

SR.

[Simon]

My 1.6 Maestro has exactly the same hose/tank set up as JUE and my heater is nice and warm. I replaced my thermostat and antifreeze (day-glo green Unipart stuff, 50% concentration) recently as part of the 48,000 mile service and the temp gauge sits about 2 notches below half way in normal driving. The thermostat on my car didn't have a bypass hole or jiggle pin. My 'stat housing was the original (there's only one design), although obviously the elbow was changed to the later one without the centre pipe. Looks like your 'stat has given up the ghost.

Stat is GTS106 and is 88 degrees C, gasket is GTG 201.

[MaestroMatt]

We had a pop at changing my thermostat on Saturday and in a moment of youthful exuberance, F153 sheared off one of the bolts. It was to be expected - you should have seen the state the other two came out in - and I would no doubt have done it myself had he not been so quick to get to the socket set but at least I can now blame him for it :laugh:. What an appalling piece of design! Luckily I have a new housing on order from Biglad (have PM'd you btw!) so I can continue to drive my car (amazingly it doesn't leak as the bolt sheared at the top of the thread) until I have fully prepared the new housing. If I were repeating the exercise, I would have a new housing ready just in case.

[Maria]

Last time I tried to do one of those I broke 2 sockets and a spanner :eek: :(

[Simon]

I've had some fun getting stat elbows and housings off too in the past and the problem is bi-metallic corrosion between the aluminium alloy castings and the bolts or studs. If the elbow or housing is stuck on, saw through the casting adjacent to the rasteners and this should free the fastener and allow it to turn. Obviously you'll need to replace the casting and a good tip is to coat the fasteners in copper grease so as to help prevent this problem in the future.

[E_T_V]

Yes the secret is lots of sticky grease. You should have seen the bodge job on our car when we got it. Yuck. You might also want to replace the bolts with larger headed ones (or even high tensile or stainless ones) to make them easier to get out next time.

[SimonR]

Originally posted by E_T_V
Take the thermostat out when the engine is cold. if it is open it is knackered. Get a new one.

Er, Guess what? ther thermostat was open and therefore knackered! Thanks Dan and others :)

I've also worked out why the old style housing works - there was a pipe going to the heater matrix that I'd not taken into account.

Oh how nice it is when a plan comes together!