Bleeding coolant system

zeaphod · Oct 8, 2019

As mentioned above, unless you are beasting the engine the lack of a fan will not make any difference. I've ran my disco conversion without a fan for years and can't get the temp above 80 something during 100 mile motorway runs, even when it's over 25degrees outside. Just one outside chance which I hope is wrong, it is possible for even newish rads to fail inside, the internals can then block the water flow. Your symptoms kind of fit in with that, but a significant part of the rad would be much cooler than the rest.

ivancrx · Oct 8, 2019

I have had the rad out and flushed it before refitting it and it was all clear then.

i have also had the thermostat out and run water through the radiator until it comes out of the thermostat housing and that is clear as well.

ivancrx · Oct 12, 2019

Right small update.

Swapped the gauge for a new one and ran it again, still no drop in temperature and ran to 100 degrees before turning off.

Took thermostat out and ran again, still getting up to around 100 degrees before I shut it off.

Radiator hot from top to bottom, all hoses hot.

I am truly at a loss now.

kermit_rr · Oct 12, 2019

Is the water pump actually giving a decent flow rate?
When you say the rad is hot top to bottom, just how hot? Do you have a probe type thermometer, ie infrared?
How hot do the pipes feel?

ivancrx · Oct 12, 2019

kermit_rr said:
Is the water pump actually giving a decent flow rate?
When you say the rad is hot top to bottom, just how hot? Do you have a probe type thermometer, ie infrared?
How hot do the pipes feel?

Just spent the last 3 hours at it, flushed the whole system with coolant flush, water now coming out as clear as it goes in, flushed water through every pipe and hose, radiator, expansion bottle heater hoses, everything.

Tested the thermostat again and it opens bang on 88 degrees in a pan of water.

Fitted thermostat again filled system and there is no difference, still running up to 100 degrees and rising before I turn it off.

Radiator at 96 degrees at the top and 93 at the bottom, thermostat housing showing 94 degrees all read with an IR temp gun.

All the pipes are too hot to hold.

Scooby22 · Oct 12, 2019

Is the water pump actually spinning or is the pulley slipping on the pump shaft. It might turn freely when tested but pulley may slip under tension. I think I would try another pump.

ivancrx · Oct 12, 2019

Scooby22 said:
Is the water pump actually spinning or is the pulley slipping on the pump shaft. It might turn freely when tested but pulley may slip under tension. I think I would try another pump.

Just pulled the water pump off and it is perfect, all spinning correctly, held in a vice and there is no way the pulley moves on the shaft.

Interceptorxj · Oct 14, 2019

So any signs of it pressurising with exhaust gasses in the system i.e head gasket gone, , was it a known engine?

ivancrx · Oct 14, 2019

Interceptorxj said:
So any signs of it pressurising with exhaust gasses in the system i.e head gasket gone, , was it a known engine?

I have had the engine for a while now, a new head gasket was fitted 0 miles ago during the full rebuild, head has been skimmed and pressure tested. No gasses in the system and no water in the oil or oil in the water.

ivancrx · Oct 19, 2019

Another day at it and still having the same problem.

In have fitted another new thermostat which was again tested in a pan of water, again this is working perfect, opens at 88.6 degrees. Fitted it filled with water and run up to temperature and again it has kept on going up and up, switched off at 100 degrees.

I am beginning to get F#*%ed off with it now.

What is going wrong?

wireman · Oct 20, 2019

Have you got the correct ratio of water to anti freeze? A minor point but antifreeze absorbs heater quicker and dissipates it quicker than just water, worth a try as you seem to have tried everything else.

kermit_rr · Oct 20, 2019

Have you checked the radiator airflow? You should be able to see through it front to back. If you can't then air can't get though to extract the heat.
It almost has to be a radiator related issue if it's full of hot water top to bottom

ivancrx · Oct 20, 2019

wireman said:
Have you got the correct ratio of water to anti freeze? A minor point but antifreeze absorbs heater quicker and dissipates it quicker than just water, worth a try as you seem to have tried everything else.

I am only using water in it at the moment as I have had it too pieces since many times in the past few weeks it would have cost a fortune in antifreeze.

ivancrx · Oct 20, 2019

kermit_rr said:
Have you checked the radiator airflow? You should be able to see through it front to back. If you can't then air can't get though to extract the heat.
It almost has to be a radiator related issue if it's full of hot water top to bottom

Radiator is quite new, less than 1000 miles with it, so I can’t see this as the problem, but....

Hicap phill · Oct 20, 2019

Disconnect the rad & run water through it just to check flow.
Can you feel air movement through the rad?

put a link pipe to remove heater matrix(just in case blocked/restricting flow or won’t bleed)

flat · Oct 20, 2019

I get a much other temperature gradient on my rad than that. Although mine is an original copper one.

It goes in at 90c ish and comes out in the early 80’s

I know you said the radiator is not very old but the internals could have failed if it’s a cheap plastic/alloy one so I wonder if something had failed internally?

The thermostat is imetalled the right way round? Sorry to ask such a dumbass question lol

ivancrx · Oct 20, 2019

flat said:
I know you said the radiator is not very old but the internals could have failed if it’s a cheap plastic/alloy one so I wonder if something had failed internally?

The thermostat is imetalled the right way round? Sorry to ask such a dumbass question lol

the radiator is as you say a plastic/alloy one so it may be the problem, I have flushed it through with water and it seems ok.

The thermostat can only fit one way, so that is ok.

I am honestly thinking you are right it as to be the radiator as there is nothing else I haven’t changed.

ivancrx · Oct 20, 2019

Hicap phill said:
Disconnect the rad & run water through it just to check flow.
Can you feel air movement through the rad?

put a link pipe to remove heater matrix(just in case blocked/restricting flow or won’t bleed)

I ran a hose through the heater matrix yesterday and that was running well, again this is new as I have rebuilt the box during my rebuild.

Dippypud · Oct 20, 2019

ivancrx said:
I ran a hose through the heater matrix yesterday and that was running well, again this is new as I have rebuilt the box during my rebuild.

If you have the choice of a new rad or repair the old, I'd go for a re-core of an old rad .... the new ones are shite ....

ivancrx · Oct 20, 2019

Dippypud said:
If you have the choice of a new rad or repair the old, I'd go for a re-core of an old rad .... the new ones are shite ....

I am beginning to wish I had kept the old one now

Bleeding coolant system

Well-Known Member

Well-Known Member

Well-Known Member

Very

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Very

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Never Knowingly Understood

Well-Known Member

Similar threads