300tdi cooling system

Hi all,

1997 300tdi Auto 105k.

I ran it dry of fuel a couple of weeks ago (15 seconds from the entrance to the filling station!!!) which may or may not be a contributing factor to the issues below....

Since i got the car i've had to regularly top up the coolant (for every tank of fuel it probably takes 1/2 a litre to 1 litre). It has a slight leak but i've never had the time to trace it. Coolant clean and no water in oil so i wasn't too concerned.

Last week, the leak seems to have gotten much worse. For the first time, there is a puddle of coolant under the car in the morning. Not much though, just a cup full.

This morning it overheated becuase it ran out of coolant. I caught it right away as the heater went cold which made me look at the temp gauge and it had started to climb. It wasn't right at the top so i don't think i will have caused any damage.

I gave it half an hour to cool down, opnened the lid on the expansion tank and there was a lot of pressure - lots of bubbles/boiling coolant and the expansion tank just about overflowed. I also noticed the coolant pipes were hard. Then the bubbles stopped and the coolant drained back into the system and the expansion tank was empty. Took a couple of litres to get the expansion tank back up to half way.

I ran it home about 15 miles and it drove perfectly - no problems at all. Temp normal.

I think i found the source of the leak whilst under the bonnet. I heard a slight hissing and it was coming from the passenger side of the engine just above the alternator. This is my first Land Rover so i don't know my way about it that well but the best description i can give is it looked like where one of the pumps bolted on to the engine block. There appears to be a gasket between the pump and the block and the hiss was coming from there. As it was hot, the coolant was boiling off before it could drip out. Whatever device is bolted to the block had a pully on the front which had the main serpantine belt round it so i assume that's the water pump.

So the questions:

1) Any opinions on the leak? i.e. leaking water pump gasket is causing it to lose coolant - not too big a problem, just fix leaking gasket?

2) May be totally unrelated but since i ran it dry of fuel and since it really started to leak coolant badly, when it's too hot it starts to stutter/loose power. It only does this when too hot and it's only done it the couple of times i've let the coolant get too low. It's as if it starts to overheat and something gets too hot and affects the fuel delivery or fuel evapourates. When the cooling system is fully topped up, it doesn't do it at all. I can sit at 70mph for hours and it runs perfectly but as it looses coolant, when the expansion tank is almost empty and the flow of coolant is interupted as a result and it starts to get too hot, this strutter and loss of starts to happen intermitantly. Unrelated and just crap in the fuel system as i ran it dry or do you think it's connected to it running too hot when it runs out of coolant?

Both times it has lost too much coolant, i've caught it almost right away as i noticed the heater going cold and stopped immediately, let it cool then replenished the coolant and it's been fine for the next 300 or 400 miles until the coolant gets too low again so i donlt think i've caused any other damage. I just need to stop the coolant leaking and hopefully it will revert to it's usual totally relaible self!

Thanks,

Chris

I had a few incidents yesterday whilst out at essex off road, speaking to a guy there he said the housing at the front of the engine often leaks and its best to strip down, use some decent instant gasket and reseal it... I suspect this is whats up with yours but having never gone that far into a 300TDi engine yet I cant say 100%, whatever it is you will need to fix it so I suggest you strip down the ancilleries and see whats what, you should be able to see whats blown but I would remove all the parts, regasket the lot and see how it goes...

whats leaking is a very common problem called the p gasket ,pet100790g is an improved metal gasket that goes between bracket and block

P gasket for sure . Fix it before you overheat the engine and damage it , the 300 is not tolerant of overheats . By the time the stock temp gauge shows its usually too late . Mods for header tank level indicators have been discussed at length here so searchs are in order .

Thanks Guys - i've just searched for threads on the P gasket and that's exactly where it's leaking. There are soem great posts on hear with pictures so that solves one problem. I'll get it replaced with a metal one!

It's only been low on coolant twice - low enough to make the heater blow cold anyway. Of those two occasions, the needle has only moved once. It was about two thirds up on the gauge when i caught it and i shut it off immediately.

You say they're not tolreant of overheats. What goes? Head gaskets?

Also, any ideas on the stuttering/loss of power?

Thanks,

Chris

Check the coolant sensor on the top of the head for the EDC system - they suffer from heat damage to the wires , especially when head has been changed and the wires not returned to the stand off clamps .

Headgasket is often the first thing damaged by overheats . Make sure your radiator is clean and gets hot all over . Does the check engine light come up when the stutter happens ? Early sign of headgasket failure can be stuttering when hot but then again you need to be sure of your fuel supply first from the tank onwards , This is covered in detail elsewhere but a quick way to check is to fit a clear section of fuel hose , again covered elsewhere .

Thanks.

Radiator gets hot all over and the check engine light does not come on. No lights on the dash illuminated at all...

i'm starting to fear the head gasket has gone..... When i topped up the coolant today, there was a lot of hissing going on and it was escaping from the broken P gasket.

Also, when i filled up the expansion tank, there was extreme bubbling going on for about 30 seconds then the tank drained back into the system. took a couple of litres to fill it back up.

Here's a question - now the coolant is filled up again, if it take it for a 10/15 minute run and take the lid of the exansion tank when i get back - how much bubbling is acceptable. Should there be no pressure at all?

Cheers,

Chris

Have you bled the system from the top of the 'stat after filling via radiator plug ? With heaters wide open ?

Nope. System is full now though. Is it worth draining it a little then trying as you suggest? What would the desired outcome be? i.e. are you thinking the system may just need bled before worrying about HG failure?

Cheers,

Chris

Just out of curiosity, i've just taken it out for a 10 minute blat. Pushed it hard to get the cooling system working. All totally normal - no pressure in the cooling system pipes and no bubbling/pressure in the exapnsion tank when i removed the lid.....

Wonder if the bubbling was just the air moving round the system since it was pumping air instead of water when the coolent went too low?

Chris

Was thinking airlock working its way out . If its cured your overheat , all well and good , if it aint broke.....

All totally sorted. It was the P-gasket. No leak and no mis-fire now. Over 2000 miles since work done.

Well worth doing!