A tale of woe.

[Tetleysmooth]

Last October, I bought my 75 1.8 non turbo. I was a bit dubious because of all the talk of headgasket problems. It went through the winter like a champ. Toasty heater, temp guage bang on normal etc. I thought I'd bought the only K series without cooling problems - until yesterday. I thought I'd change the thermostat, just to be ready for the warmer weather.
Fitted the 'stat ok and refilled the cooling system very slowly so as to minimize the risk of airlocks. That's when the shenanigans started. To cut a long story very short, I think a previous owner had put leak stopper in the system. It now keeps building excess pressure and the heater is stone cold. Also had a major leak from what I believe to be the water pump. The coolant is leaking from the drivers side of the engine - fast.
Is there anything I can do to eliminate the possibility of an airlock in the heater? Personally, I think it's terminal. It's parked up at our warehouse at the moment. I ran it again today before I came home from work, and although the temp guage didn't rise above normal, the heater remained stone cold. I'm thinking the worst and am absolutely gutted, as it's a car I thought I'd be keeping for a good while.

Meanwhile, has anyone got a ULEZ compliant 75 auto they wish to part with at a reasonable price (cheap). I won't hold my breath, but it's worth asking.

[stevestrat]

This is the MGR procedure for draining then refilling the coolant on a K series:

Originally Posted by SD1too

Here is the MG Rover official method for draining:

1. Remove expansion tank cap
2. Disconnect heater return hose from rear of cylinder block
3. Disconnect bottom hose from radiator.

Here is the MG Rover official method for refilling and bleeding:

1. Reconnect bottom radiator hose and heater return hose to engine block.
2. Disconnect hose from bleed valve. Attach suitable tube and blow through to ensure that valve pin is not sticking. Reconnect hose to bleed valve.
3. Remove bleed screw and fill cooling system keeping level at neck of expansion tank.
4. When a steady stream of coolant is emitted from the bleed orifice, refit bleed screw. Continue filling until level remains static at expansion tank neck.
5. Turn off air conditioning by selecting 'Econ' mode [this is only to prevent the radiator fan running constantly].
6. With expansion tank cap off, run engine at 1500 - 2500 rpm whilst keeping coolant level at expansion tank neck. When level rises, fit cap.
7. Continue to run the engine at the same speed until the radiator fan starts running. [In practice the engine may not get hot enough for this.]
8. Reduce engine speed to idle until fan stops. Switch off engine.
9. When system is cold, check level in expansion tank and top-up to the 'Max' marker not the expansion tank neck. [In practice you may have to do this a few times after a journey before the level stabilises.]

Simon

[Tetleysmooth]

Thank you Steve, but where exactly is the bleed screw? I didn't notice one yesterday when working on the car. The car is a 2004 model.

[Matt_75]

Originally Posted by Tetleysmooth

Thank you Steve, but where exactly is the bleed screw? I didn't notice one yesterday when working on the car. The car is a 2004 model.

It's between the engine and air filter housing

[nh627]

Great description of the K series woes with the stat. I changed mine a couple years ago and it took 2 attempts to bring it to heel! It is tricky to seat the thermostat in the coolant tube and block so you will need white grease or similar lubricant, then it will be patient bleeding, massage the hoses to shift any air with the heater fully open, check the fitting to ensure the heater valve opens. The fact that it worked well previously does point to an issue on install, but they pigs with engine installed sorry to say.

[Tetleysmooth]

My stat is in one of those plastic casings with three outlets.
Fitting that was the easy part. Might have to drain and refill again when I get time, using the bleed screw.

[suzublu]

Originally Posted by Tetleysmooth

My stat is in one of those plastic casings with three outlets.

Fitting that was the easy part. Might have to drain and refill again when I get time, using the bleed screw.

PRT 😎 or Pressure Release Thermostat

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