how hot is hot

[dansk]

We had a bit of an adventure getting our t25 back to blighty from france last month after the water tank bled dry. the warning light failed to warn, but the smoke billowing out the back certainly did the trick... It was very hot day and we'd done about two hours driving before the emergency. After we limped back - some 500 miles, with the over heating forcing me to pull over every hour or so to let her cool down. Not being mechanically minded, I don't know what the problem is, but I bled the air out of the radiator and put in some radiator sealant and drove back very, very carefully. The vans just gone in for MOT and Im hoping that we haven't damaged the engine - she's just had a new head gasket put in for petes sake!

I did wonder before we went if the engine was running too hot. the garage insisted that they had tested it thoroughly, and I believe them. You just can't really test 34 degrees sunshine and mountain roads.. but how hot do these engines get when just driving in normal england conditions? This is my first campervan so I don't really have any clue. Does turning on the fan heater help much? Looking around the forums, it seems to be a fairly common issue.. what can we do to help keep her from overheating when driving hot summer days? Is it normal for the water in the main radiator tank to be almost too hot to touch after two hours?

[kevtherev]

87 deg is when the thermostat opens. (petrol)
105 deg is when the second stage fan comes on.

after that aluminium engines warp and leak

the cooling system is perfectly adequate to cope with hot summers.
if it doesn't, then the cooling system is faulty.

My cooling system has just started to be a concern.
At high speed the gauge moved 3mm too far past the led for my liking.

[AdrianC]

Is it normal for the water in the main radiator tank to be almost too hot to touch after two hours?

The water in the tank should be FAR too hot to touch within a minute or two of starting the engine - the thermostat, as Kev says, doesn't open until mid-80s degrees C. That's deep into scalding territory.

My cooling system has just started to be a concern.
At high speed the gauge moved 3mm too far past the led for my liking.

I'm surprised you're even getting high fan on, Kev. Low should be able to keep it under control in all but the most extreme of high-ambient-short-turnoff-heatsoak-after-long-fast-m'way-run circumstances.

I suspect the most common causes of overheating are low level due to leaks and knackered blocked radiators due to infrequent coolant changes. As with everything - breakdowns are due to poor maintenance, long and short term. Check your fluids regularly and change them as scheduled, and you'll avoid the vast majority of problems.

[dansk]

Thanks.. You're dead right about the maintenance, we don't do nearly enough. It be good to find someone who can give us a run down on it all..to be honest don't know how to or how often we need change the coolant for instance..

[AdrianC]

to be honest don't know how to

Draining and refilling's easy enough - dispose of the old via the tip or a local garage. Bleeding's covered in the wiki, and nowhere near as difficult as it's feared. If you've not got the Bentley manual (see the member's area for details), get it. It doesn't fully cover the JX turbo diesel, but it's close enough with a bit of backup from here for the differences.

or how often we need change the coolant for instance..

If you've got the blue-green stuff, two years is the lifespan usually quoted. The red stuff is not only better for the engine internals, but has a five year life.

Brake fluid's also every two years.

[dansk]

Cheers.. Do know how to, and have bleed the radiator but not the other stuff, which was changed out by the garage recently anyway. If the engine and the radiators ok that hot then I guess there must be fault somewhere else in the system.

If the cooling system is working well, no leaks or problems etc, is there a limit to how long you should run the engine, especially in hot weather? Would you say it's not good idea to go long distance if its thirty degrees plus?

[AdrianC]

If the cooling system is working well, no leaks or problems etc, is there a limit to how long you should run the engine, especially in hot weather? Would you say it's not good idea to go long distance if its thirty degrees plus?

Nope, it's absolutely fine. It gets up to working temperature within a relatively short time, then - if all's well - it'll just stay there. No matter how heavy the traffic. It's designed to do so. Remember, they sold these vans worldwide - even in the deserts of southern US.