Radiator flush stuff (engine)

[julianf]

This vehical was sold as spares or repairs. I fixed the initial issue back in 2015, but I have some hazy memory of the previous owner mentioning intermittent overheating.

I might be making that up now.

I drove the vehical from Eastbourne (south coast, along from Brighton) to Devon after purchase. It ran badly (due to the initial issue) but there was no overheating.

The prior issue was that the Woodruff key on the crank sprocket was worn along its side (almost certainly due to under torquing of the crank nut) and that would allow the timing to change whilst driving. Easy enough fix once found. So (probably) unrelated to this issue.

 

[tom2207]

take the thermostat out to start with ,,, top it up with water from cold and see if theres water flow , and or bubbles ,, id be edging towards not being bled properly the first time ,, its only ten min of work and see whats going on ,,, the flow will tell you the water pumps working , or not , bubbles for head gasket / also worth of a listen at the back of the block / head they usually start to get a bit blowy there first.
although if they have had a good toasting they can oval the bores , 200s never did , some 300s can ,,,

 

[julianf]

take the thermostat out to start with ,,, top it up with water from cold and see if theres water flow , and or bubbles ,, id be edging towards not being bled properly the first time ,, its only ten min of work and see whats going on ,,, the flow will tell you the water pumps working , or not , bubbles for head gasket / also worth of a listen at the back of the block / head they usually start to get a bit blowy there first.
although if they have had a good toasting they can oval the bores , 200s never did , some 300s can ,,,

I'd considered taking out the thermostat, but wasn't certain it was possible. The stat has the seal around a metal disc. I think I could possibly get the seal off (it comes with the stat) but without the disc, I'm not sure it would keep form anyway.

It's this seal that seals up the housing.

I guess the faces may mate up ok with some blue stuff though.

 

[julianf]

I have a spare block and head on the garage floor and another 300 in a breaker disco. But I'm hoping that fixing this one is going to be quicker than swapping the engine.

However the vehical is a collection of previous owner bodges. Pretty much anything that can be wrong on it is wrong.

It was an honest sale. He seemed to be amazed that I was planning on driving it home. And then he found out I lived 5 hours away.

(It still had some mot on it, but I reckon that one was by post)

 

[tom2207]

I'd considered taking out the thermostat, but wasn't certain it was possible. The stat has the seal around a metal disc. I think I could possibly get the seal off (it comes with the stat) but without the disc, I'm not sure it would keep form anyway.

It's this seal that seals up the housing.

I guess the faces may mate up ok with some blue stuff though.

cut the two legs and throw the middle away , use the frame as a washer that will do , for eight quid or what ever get it out of the system ,, or cut up the old one if you still have it and do the same

 

[tom2207]

takes 600 quid these days to bore and put pistons in a 300 ,, set of bearings and a crank polish ,,, friend did one last week ,,, it was breathing badly .

 

[octo0072000]

did you test new stat in boiling water before fitting i have had faulty one's new with viscus fan when hot can you stop the fan with a hammer shaft lump of wood if so it's u/s

 

[sako243]

I'd considered taking out the thermostat, but wasn't certain it was possible. The stat has the seal around a metal disc. I think I could possibly get the seal off (it comes with the stat) but without the disc, I'm not sure it would keep form anyway.

It's this seal that seals up the housing.

I guess the faces may mate up ok with some blue stuff though.

If you take out the stat then you should be getting maximum cooling, if that doesn't work then you've got a blockage somewhere.

I had that with an engine off Bob. Heater wouldn't warm up and neither would temperature gauge because it was flowing through the rad constantly.

 

[tom2207]

did you test new stat in boiling water before fitting i have had faulty one's new with viscus fan when hot can you stop the fan with a hammer shaft lump of wood if so it's u/s

yep you can ,,, as long as its going round its doing all iit needs on a 300 ,, I cant remember if they have a lock bolt on them or not , they give no bother ,,,

 

[reb78]

From memory, if the heater is hot, liklihood is that the stat is open.

Viscous fans arent hugely needed on these tdi's. It wouldnt overheat to this extent without a viscous fan if all working fine otherwise.

Have you got an IR thermometer Julian? Mine will read 88c at the temp sender when my 200 is up to temp.

 

[tom2207]

From memory, if the heater is hot, liklihood is that the stat is open.

Viscous fans arent hugely needed on these tdi's. It wouldnt overheat to this extent without a viscous fan if all working fine otherwise.

Have you got an IR thermometer Julian? Mine will read 88c at the temp sender when my 200 is up to temp.

you get enough flow through the pipet hole to warm the heater all be it slowly with the stat closed ,, or even partially open ,,, just take it out and rule it out

 

[reb78]

you get enough flow through the pipet hole to warm the heater all be it slowly with the stat closed ,, or even partially open ,,, just take it out and rule it out

Thats fine. I agree to remove it but with the heater on full chat it would cool that water if its coming through the pinhole i would think?

 

[julianf]

Old stat had been badly installed, so the seal was all mashed up.

You can buy a britpart stat for £3 though (i did not, but you can)


A point to note -

The old stat, when i took it out, was partially open. I was hoping that it had jammed, and was therefore restricting the flow.
I even put the new one up to my mouth and blew, and, sure, enough, not open at all (at room temp)

This doesnt mean a lot, but it was overheating with a stat that was jammed (partially) open, and is now overheating with a brand new (genuine) unit that, may, of course, be jammed shut...
Ill work out a way to take it out, but i cant say im confident!

 

[tom2207]

Thats fine. I agree to remove it but with the heater on full chat it would cool that water if its coming through the pinhole i would think?

nope ... not that fast , think about how long a mug of tea takes to cool , one pass through the matrix wouldnt cool it totally .

 

[tom2207]

Old stat had been badly installed, so the seal was all mashed up.

You can buy a britpart stat for £3 though (i did not, but you can)


A point to note -

The old stat, when i took it out, was partially open. I was hoping that it had jammed, and was therefore restricting the flow.
I even put the new one up to my mouth and blew, and, sure, enough, not open at all (at room temp)

This doesnt mean a lot, but it was overheating with a stat that was jammed (partially) open, and is now overheating with a brand new (genuine) unit that, may, of course, be jammed shut...
Ill work out a way to take it out, but i cant say im confident!

it rules it out of the equation though ,,,

 

[Bornfree]

When it's overheating is the bottom hose hot or cool ?

 

[julianf]

takes 600 quid these days to bore and put pistons in a 300 ,, set of bearings and a crank polish ,,, friend did one last week ,,, it was breathing badly .

Ive got one running in a disco, with a knackered turbo, and one head / block combination on the garage floor, and another head and turbo on a shelf somewhere.

My casual plan was to build one of these up at leisure, and then swap it in at a later date. I wasnt in a rush to do it though!

 

[tom2207]

theres a bleed screw on the top of the rad as well as the other two ,, or there was on the one I was at last week.

 

[julianf]

When it's overheating is the bottom hose hot or cool ?

I forgot to check. But its a new radiator, so, unless its got a bag over it, or an Exocet attached to it, its going to be something other than "hot", right?

 

[julianf]

theres a bleed screw on the top of the rad as well as the other two ,, or there was on the one I was at last week.

yep... done.