Overheating 2.5TD

[dan9090]

Hi all,

Up until last Sunday I've never ever had a problem with overheating, it always hovered just below half on the gauge when warmed up.

Last Sunday I have to admit she ran out of water and in the mean time of course overheated. Replaced water, cleaned radiator off of mud etc but on a longer run the temperature is still rocketing. Any suggestions as for next steps?

Thanks, Dan

[western]

check the thermostat is working as it should open @ 88 degrees, bottom 4 rows of radiator fins engine side, these rust away to dust & can cause high temp readings --- a recored or replacement rad will cure it.

[disco tony]

Look inside oil filler cap for white sludge (emulsification), this is a quick check for head gasket. Is it still loosing water? Have you checked for obvious leaks?

[Les Henson]

How quickly does the engine overheat from cold?

Les.

[FridgeFreezer]

Did you *really* clean the rad of mud? Getting all the mud off the front is not the same thing as cleaning all the mud out so that you can see daylight through it (and air can flow through).

[dan9090]

Thanks for all the suggestions. Some more details in response.....

I will give the rad another good blast with the jet wash.... i have to admit you cant quite see daylight through it yet

It takes probably 20 mins before overheating and only seems to start when at "high" speed (say 50 mph +) .... if you back off and start trundling along at 30/40 the temp seems to back off.

Will check the bottom row of fins this morning and report back.

Will also check the oil filler cap for white sludge and report back.

cheers

[dan9090]

sorry guys, ive been a muppet and forgot to say that since this problem started ive been getting barely any heat from the heater (before this it used to get nice and toasty) so im sure this has something to do with it, any ideas?

[FridgeFreezer]

Air lock in the system then?

[dan9090]

how do i check for an airlock and then fix it?

sorry, doing a lot of things for the first time on this (my first) landy

cheers

dan

[Les Henson]

If the thermostst was stuck closed the engine would heat up very quickly. If it was stuck open it would take an age, but it would get there in the end and the heater would eventually work ok. Hotter at high revs and cooler at low points at blocked rad/restricted coolant flow around the engine. You're not getting air bubbles rising in the header tank are you?

Les.

[David Sparkes]

Responding to your 'first Landy' comment.

Air Lock.

I tend to agree with this as the heater isn't working. The lack of coolant in the system may also contribute to the high load overheating.

It's possible muck has been dislodged and is caught in the narrow restriction caused by the heater tap. Remove the tap and clean the internal passage way. A small wire brush sold for plumbers to clean the internals of copper pipe may be useful here. B&Q, Wickes, etc, should supply.

With the engine cold, leave the radiator cap in place but open the highest hose to metal joint in the system, this is probably one of the heater pipes. Put a funnel in the hose end and Slowly pour in coolant. Slowly should allow the air to come out as well as coolant flow in. Eventually coolant will come out of the metal pipe you took the hose off. Reconnect the hose and that should get the heater working.

If it doesn't get as hot, or takes it's time warming up, get the engine hot and equip yourself with heavy waterproof gloves (not the skinny latex / nitrile ones). Leave the cap in place and start to open the same joint. Beware the pressure will force some hot coolant as well as hot air out. When it seems the flow is all coolant (perhaps after a couple of seconds) reclose the joint. When the engine cools down, top up as required.

If the heater works for a couple of days, then stops, repeat the air bleed process, but it's an indication air is getting into the cooling system, probably from a blown headgasket, but do recheck any disturbed connections for leaks.

Radiator cleaning.

I was taught (but I don't do mud plugging) that a power jet wash was not good for the external cleaning of radiators. Neither was attacking the radiator from the easy side (the front).

Working from the front pushes muck further back into the core, where the jet can't get to it, and the power of the jet will bend over the fins, further preventing access of both cleaning water and air.

This time I'd take out the radiator and just use mains water pressure from the rear. As it's a new to you vehicle this extra work will enable you to gain a good idea of the physical condition of the fins etc. Take the opportunity to straighten bent fins, and also reverse flush the radiator internally.

If this extra cleaning doesn't put you off mud plugging, consider making up a lance that will fit on the garden hose, go down between the engine and the radiator, and squirt water out sideways. I'm thinking a 15mm copper pipe, closed off at one end, with a slot cut in one side about a inch from the closed end. After the slot is cut with a hacksaw, 1/3 to 1/2 way through the pipe, squeeze the pipe around the area of the cut to make the pipe oval. This will leave the slot pointing one way. Now you can clean the radiator from the rear without damaging the fins.

Just think how lucky you are with the weather. November, it 'ought' to be freezing when playing with all this water.

Have fun.