expansion tank bubbling

I just got my first discovery, I'm totally new to 4x4s. I got it the other day off a guy who drove 70 odd miles to me and everything seemed fine. The next day i started it up and the water in the expansion tank was bubbling like mad i kept it running and kept topping it up and after about half an hour it was fine so i drove about a 3 mile round trip the temp stayed at half. The expansion tank is not the right one for the truck (i will get the proper one). I put a new thermostat on today (there wasnt even a thermostat on it) for some strange reason. It wouldnt start but I managed to start it by putting my foot on the accelerator in the end.
The bubbling wasnt present at first but it did start bubbling but then stopped again.
Any ideas?
All help gratefully recieved.
Thanks in advance

Y did he remove the thermostat in the 1st place must av b8j overheating and he removed it to keep it flowing thru. Id get head pressure tested. And check everything to do with the system rad pipes and make sure its bled

I do not know why it was removed seems a daft thing to do to me. I heard they are difficult to bleed properly. Im off to get the proper expansion tank now off someone who is breaking one

I am surprised the temp got up halfway with no stat fitted. I would be wondering if the rad was blocked.

How can i check this?
Also the latest i now have the correct exoansion tank not fitted yet but it only has 2 connections for pipe to go on to yet the one that is on the car has 4????? Confused.com

Before taking the head off, it might be worth getting a cheap tester kit to see if there is exhaust gas finding its way into the coolant. Something like this: http://www.ebay.co.uk/itm/BLOCK-HEA...ID-/271567145713?_trksid=p2141725.m3641.l6368 Alternatively, most garages should be able to do it for you if you don't want to buy the kit. If that shows up positive then you'll know that it's probably the head gasket or worth getting the head pressure tested. At the moment I wouldn't get too sidetracked about the expansion tank - when I was young very few cars had these! If I was you I'd be more interested in eliminating the possibility of a head gasket failure or a head crack.

First of all it appears that we have been left to guess the engine u have, or have I missed something

The header tank has two large diameter hoses, the flow and return plus two smaller diameter air purge hoses.

To test the radiator, there wouldn't be any water flowing through the radiator if it was blocked, simples, although it maybe partially blocked, but then isn't a easy to tell this without an inspection of all the tubes the radiator has which is usually done by dismantling it.
If plain water only has been uses then it is likely u have an iffy radiator with some of the tubes blocked.

Also unless you got it very cheaply I'd be on the phone to the bloke who you have just bought it off

Sorry it is a 1995 2.5tdi.
I think the pipes are all wrong to the expansion tank. The tank thats in is not the proper one i have a pipe from the thermostat that splits into 2 and they are both in the expansion tank. Then i have one straight from top of rad into expansion tank then another that comes from down under the fan somewhere and into tho expansion tank. But now i have the proper tank it only has a connection for 2 pipes.
I will get the head checked.
But the expansion tank cant be helping if the pipes are wrong

If its the head ill go to his house

TattooMan said:

If its the head ill go to his house

Click to expand...

Caveat emptor?

Seemed honest enough explained it was the wrong tank but it wasnt doing it when he brought it like i said though after about half hour it stops its deff a strange one.