Hello I'm a relatively new townace owner and have had some problems re. overheating. I own a 1990 super extra 2ltr tdi.
I experienced some overheating while on a motorway journey and backed off on the accelerator and the temp returned to normal, put that down to steep hill etc like this site mentions. Every thing ok for a while then disaster, another motorway journey later complete loss of coolant,loads of steam, nursed it back home with frequent top ups of water.
Turned out to be a split in the main rad along a seam, had that reconned and everything was ok in normal driving conditions.
Another motorway journey later and everything seemed ok, temp gauge rock solid on the mid point as usual, then approaching our destination we're off the motorway and into normal town traffic and I hear the expansion tank bubbling and spot some steam, pull over as the temp gauge climbs, allow the engine to cool and find that there's been some coolent loss, top up and resume journey. There is no visible leak from under the vehicle or from the top while running the engine so I am baffled as to why this is happening
as it only seems to happen when the revs are low after a journey at speed, also the heater blows cold when the temp starts to rise so this makes me think the coolent suddenly drains from the heater rad.
Any ideas?

- (#8549) Jorge Seabrook, 15 Feb 04 14:04

Head Gasket.

- (#8549) david miller, 15 Feb 04 22:23

Hello Jorge.
If it has a tendency to over heat at motorway speeds, then cools once the speed has been reduced, it would suggest that the viscous coupling is failing.
The coolant loss you describe will have been as a result of the coolant within the engine boiling, then turning to steam and forcing some coolant out of the expansion tank.
Replace the radiator cap first, and make sure its a Toyota cap rated to 0.9 BAR, they are well known for causing overheating events. Then keep a close eye on the condition of the coolant, if it starts to darken in colour or if it has turned black, then you will have a blown head gasket, and or cracked head.
- (#8549) dave Bright (Bournemouth), 16 Feb 04 01:22