Cooling System & Heater

[joe90]

Ok, so where do i start with this one....

I have a 300tdi, that seems to be using water. On a monthly basis im having to put 4L into the cooling system. The temperature needle shows the running temperature as normal.

The first hint i get of it loosing water is when the heater only blows hot air whilst in motion, and cool air whilst stopped at lights, and or idleing. Eventually this gets prgressivly worse until the heater doesnt work.....(prob because its got no water in it!!!)

There is no water apparent in the engine oil, and the engines performance is otherwise perfect, nor is any water evident dripping from the exhaust.

Originally i thought it was a faulty thermostat and promptly changed it, but this has not cured this problem.......

Does anyone have any ideas as im now at a complete loss. No split hoses are evident, nor is dripping when parked up after the usual comute to and from work.

[petergalileo]

You could increse the amount of anti-freeze in the system give it a couple of weeks then start looking for blue crystals which would indicate where the leak is.

You could try adding a bottle of radweld, I know they say its only temporary but my dad had it in a sierra for years !

4 litres a month is a hell of a lot of coolant to loose without some visible leak.

Mine looses about a pint a month but mine leaks at the top hose where the thermostat sensor for my fans goes in, theres a nice build up of light blue crystals there.

[beast5680]

could possibly be the engine is burning it off due to a head gasket leak?

[dazzawhipple]

If I remember the 300 TDi are prone to the 'P' Gasket leaking (water pump area) There should be a stain at the back of the water pump and the main block or its the head gasket gone


If I have described it wrong somebody will be along to put you right


Darren

[Bobtail]

I've had the same problem....

I have done the p gasket as this was leaking

I have changed the thermostat

Then last week my rad died on me proper on way home from work

piggy back time again.........this seems to have done two things

1:temp gauge now never gets above 1/4
as to 1/2 before new rad

2:have checked water regulary past week(every day)
all seems ok will keep you updated

so my advice check your rad for any small signs of leakage

good lock

[muddyweb]

Just to echo what's been said.

Water pumps and 'p' gaskets are favourites on the 300.

Have a good hunt around the front of the engine and look for signs of leaks.

[joe90]

If there was a leak on the head gasket, surley i would notcie a drop in power and performance? which i havnt.

Had to change the power steering pump earlier this year, so looks like the water pump 'P' gasket is next - dare i sask tho - is this a hard job !!!!

[ChrisW]

Problems with the cylinder head may not generally manifest themselves as the head gasket going - my cylinder head gasket was perfectly fine, it turned out the cylinder head had a crack between the water jacket and the exhaust port - the only evidence of there being a problem was the overheating, the water level dropping and steam coming out of the exhaust.

[ChrisW]

To replace the water pump / gasket see below - the P gasket is actually mounted behind the 'second half' of the water pump - the cast aluminium section that looks like part of the timing cover - this comes off seperate to the timing cover (fortunately) and the P gasket is located there.
If you replace the P gasket make sure it is the 'uprated' metal gasket designed to overcome the problem of this gasket leaking.

[joe90]

Thanks for the chris, im off down the local spares counter to get the bits, will have an ask. Theres no steam coming from the exhaust, so im confident it is this problem

Will let you all know one way or another, looks like i can finally use my new socket set santa got me  :lol:

[Range Rover Blues]

I've had the same and it was a pinhole in the hose, looked fine from outside, inside it had delaminted and collapsed.

Anti freeze BTW lowers the surface tension of water, for those who are going :? huh? that means it will leak a lot more when you add anti freeze, many a water pump has gurgled it's last when the anti freeze was replaced ready for winter.

[joe90]

well got all the parts, p gasket (new metal one) water pmp gasket, more antifreeze - just waiting for the weather to make its mind up!!! its not sure weather it should snow or rain here so it seems to be doing both.

Got a feeling im gonna get wet and cold

[robbie]

Got a feeling im gonna get wet and cold

go on, you know you want to ;)  you wont sleep yonight if you dont give it a go.......

I am watching this with interest as I also have a 300TDi.

Keep warm and keep us posted :)

[joe90]

Well its half time in the P-gasket change. Just come in for a warm up brew. The first part of stripping the belt tensioner, hoses, pully from water pump and power steering all went remarkably well.

The second phase of stripping the second part of the pump has slowed me down. As i couldnt find a socket to fit into the rescess containing the fixing bolt, otherwise hidden behind the belt tensioner. (Think that made sense.)

Just two bottom fixing bolts to go and shes off, and were flying. - Pics to follow.

[joe90]

pics as promised, got wet and cold, and when put back together, my water pump started to leak grrrrrrrr

[Skutter]

Had the same problem with mine last year, turned out to be the P gasket (the difficult one to get to, behind the water pump bracket). By the way, might pay to replace the two plastic fill plugs (one on top of the 'stat housing, the other on the rad) these can crack at the top of the thread and act like a pressure valve.
Best of luck. [-o<

[joe90]

Thanks skutter, didnt find it to bad a job to get to - the only bolt i had problems with is the one hidden in the belt tenssioner mounting. Put it all back together tho, filled her up with anti freeze and ran it and just when i thought we were getting somewhere i noticed a water leak. Turned out that the seal in the water pump had gone. so had to book a day off tomorrow to get a pump, as nobody was open for parts lol