HELP My 300TDI is killing me

[dero]

I have a repeating problem that no one seems to be able to solve .
Pressurized coolant leading to overheating .
History...Over a period of 6 years / 230,000Km
3 motors recond inc. different blocks...plus 3 new heads...plus 1 skimmed head...plus 3 new radiators [ satisfy motor warranty ]...plus several new hoses & t'stats & water pumps etc .
After 750,000 km of trouble free motoring , usual maintenance , I decided to replace the motor as it was getting tired & I wanted a good motor ready for retirement .
Turned out the motor was fine , turbo was tired .
2 of the motors were done by well respected professionals , 1 by local mechanic .
Most of the work done by well known & respected L R independent workshops .
This is killing me , financially , work loss & recreation . [bigsad]
Any ideas [ please read all the above ] would be greatly appreciated .

[TonyC]

Hi dero,

Sorry to hear your woes.

What sort of temperature are you seeing?

How is it being measured? Standard LR gauge, block or head temp, aftermarket coolant gauge?

When you say it's pressurising, is it pumping coolant out the expansion tank?

Has it being over heating from straight away when the moter was rebuilt? Or was it OK for a while?

When the head was removed for subsequent rebuilds/ head replacement was the head gasket OK? It sounds like head gasket, but seems unlikely with all the rebuilds/heads it's had.

Is the heater blocked off?

Tony

[dero]

Head temp 85 to 90 , coolant steady on 1/2 std gauge , runs fine .
I keep bleeding the air out until I can get it looked at , slowly gets worse with time .
occasionally I have been caught out , going good then , cooked motor .
use of the car has not changed since I got it , work , fun , towing , mostly open road with a little town work .
Never had a problem before , 750,000 km .

[dero]

Starts off filling the expansion tank , not blowing out unless catastrophe .
At the moment , average is 100 km bleed in the morning , no loss of coolant .
Hoping to drive it to Perth when they open again .

[dero]

Heater has been bypassed for a long time .

[dero]

Mechanics suspicions , possible HG failure & once an intermittently faulty thermostat not opening [ one in 10 ]
Seems like head gasket failure , but why ?

[TonyC]

85-90 isn't overheating.

Or are you saying it slowly builds up air in the cooling system, and then has a catastrophic overheat?

Does it lose coolant?

It should self blend air from the system through a small hose coming out of the thermostat housing, one out of the top of the radiator, through the "3 way ejector" and into the expansion tank.

I believe the "3 way ejector" is a one way valve, but I i have heard of them being swapped for a brass T piece.

192213

Tony

[TonyC]

Heater has been bypassed for a long time .

Bypassed or blocked off?

I believe is necessary to have coolant flowing, so you need a hose from the motor outlet looped back to the inlet, not just blocked off.

I don't know what happens if it's blocked off.

Tony

[TonyC]

Mechanics suspicions , possible HG failure & once an intermittently faulty thermostat not opening [ one in 10 ]
Seems like head gasket failure , but why ?

My young fella's D1, we bought with a blown HG, then he did a heater hose and HG, then another HG.

The machine shop that machined the head suggested injectors, they were leaking badly and terrible spray patterns.

We replaced them and it's been good so far, touch wood.

Tony

[dero]

Slow build up of air in coolant , no coolant loss .
3 way bleed all good .
Injectors new with 2nd motor , under 100,000 km

[dero]

Heater is bypassed , full flow .

[TonyC]

Have the symptoms been the same across the 3 replacement motors, heads and radiators?

If so, that would point to something external to those items.

Tony

[dero]

Yes , but I can;t think of anything that hasn't been replaced . Several times .

[dero]

Has Elring been taken over by Britpart ?

[Tins]

Has Elring been taken over by Britpart ?

No. Elring is bigger than Britpart. Still German.

[V8Ian]

Mine would randomly overheat, it cracked the expansion tank. The root cause was a blocked muffler.

[Graeme]

That just jolted my memory about a comment by my father around 60 years ago!

[Tins]

One thing about 300TDis is they are notorious for having difficult to bleed cooling systems. Apologies if you already know this.

Our resident guru, Dave, often talks of the "coke bottle trick (https://youtu.be/zDB5FFidJgY'si=Zi6S78dzNpsnzU4z)". Might be worth a try. The linked vid is his, as is the follow up one.

[350RRC]

Slow build up of air in coolant , no coolant loss .
3 way bleed all good .
Injectors new with 2nd motor , under 100,000 km

I'm assuming the radiator cap is on the radiator and the expansion tank has some sort of solid cap, doesn't really matter.

Have you replaced the radiator cap ever? Is it the right cap?

The pressure cap has 2 functions............. to let pressure out, then let air or coolant back in as the coolant shrinks in the block (depending on the set up... on an old RRC the overflow tank is pressurised and the pressure cap sits on that).

If the little return valve in the cap is faulty (stuck) when the block is cooling it can suck air in from somewhere.

I've had this problem on 2 cars.... a 74 RRC and a 99 Courier. Did my head in the first time with the RRC, same symptoms as yours but the cast iron heads on a 350 are very forgiving.

The little return valve in the cap can be 'unstuck' but it seems to be a very temporary solution and in both my cases a new cap fixed it.

If your pressure cap is on the radiator make sure it is the right one for that particular radiator because there are variations between manufacturers...... a new Denso radiator in the Courier required a different cap from stock.

Good luck! DL

[dero]

The cap with the valves is on the exp tank & has been replaced several times through the debacle .
I bleed the system with a replacement cap with a hose siliconed into it , remove the plugs & blow into the hose to purge the air , then refit the cap . Seems to work well .

[sharmy]

A mate had a D1 with the 300 motor and suffered overheating problems. Mechanics diagnosed cracked head or block and mega bucks to fix. Finally found the thermo fans were not working properly, replaced, and had no more problems until sadly he passed away.

[dero]

Over heating isn't the problem generally , eventually the air lock causes melt down .
The motor does not slowly get hotter , the air lock stops the cooling system working .
Viscous coupling has also been changed .

[dero]

The third motor was from turners in UK just to eliminate any possibility of a cracked block etc .

[V8Ian]

When my muffler caused overheating, it was intermittent. The muffler would be fine, then something internal would move, causing a sudden overheat situation.

[DazzaTD5]

I have suggested to the OP to have a chemical test done on the cooling system to see if there is any hydrocarbons showing up.
I suspect the answer will be a yes. Preferably get the test done by someone that has no history with the engine.
For that matter the OP could buy a kit from their local parts place and do the test themselves.

[loanrangie]

I would have given up after the 2nd engine and stuffed a 4BD1 in there and called it done.

[dero]

I had the same thought , but I am too far down the hole .

[dero]

I had the test done by a local shop with no prior involvement . He used a colour change liquid tester for over 1/2 hour on the workshop floor , idle , revving hard etc , result was negative .

[shack]

I had the test done by a local shop with no prior involvement . He used a colour change liquid tester for over 1/2 hour on the workshop floor , idle , revving hard etc , result was negative .Diesels are a lot harder to test for combustion gases.

We have tested a couple that we essentially knew were gone and they came back negative. One was literally filling the radiator with gas and it wouldn't show. On the test, it didn't get hot either, just blew all the water out of the radiator.

Head gasket was gone between 2 cylinders on the fire ring.

No guarantee that's your problem, but a negative test is not conclusive either.

[shack]

At the end of the day you should be able to Sherlock Holmes it:

"When you have eliminated the impossible, whatever remains, however improbable, must be the truth"

It's either combustion gases or air, there's no other options to my mind, I cannot think of any way that air can get sucked into the system unless there is a radiator flow restriction on the way into the pump and the pump is sucking air in somehow.

I've never heard of that myself and think it's extremely unlikely.

So you are down to 1 option....

[Robmacca]

Not sure if this has been mentioned or even if it's related but I had a similar issue and it was discovered that I had connected the cooling system valve incorrectly causing me grief...

192453


Just ignore if this if I'm totally off the mark ;)