Conference terri::cars_uk

    The top hose probably blew because it was old and not as strong as it
    used to be. When the engine heats up the pressure in the cooling system
    rises. There is a limiting valve (usually the radiator cap) which
    prevents the pressure rising high enough to burst the pipes. Maybe your
    radiator cap is the wrong pressure, or may be the pipes are just plain
    old. If the pipes were strong enough then you would find that the
    pressure relieve valve will open, and you will start to lose coolant
    (as steam). This should only happen when the temperature gauge goes
    into the red band. 
    
    If you replaced the top hose you shouldn't suffer the same problem
    (though it might be wise to replace the bottom hose as well !), but you
    might still have to slow down or stop if the engine gets too hot (and
    check for escaping steam). It would also be good to keep an eye on the
    coolant and oil levels. Check them carefully before you set out to tow
    on a hot day !
    
    As to why the engine is getting too hot. There are a number of problems
    that can cause overheating (bad head gasket, wrong mixture setting, low
    coolant level, air lock in cooling system, worn out engine etc). Or you
    might just be expecting too much from the car when towing. It might be
    possible to add an oil cooler to help keep the engine cool. A garage
    ought to be able to run some tests to see what the general engine
    health is like (how many miles has the engine done ?)
    
    Andrew

    I've towed all sorts behind various cars and never had an overheating
    problem in hot weather.  I do know that the car instruction books
    sometimes suggest fitting an extra cooling fan.  You could try that.
    Ken 

>>I do know that the car instruction books sometimes suggest fitting an extra
>>cooling fan

Without getting into to much hasle I agree that a good and cheap solution is
to fit an extra cooling fan.
Another idea might be to place a switch in your car so you can switch on
your fan at an earlier stage and have it turning as long as you want trying 
to prevent that your engine gets that hot at the first place.

Just an idea,

Peter.

    I imagine the fan is currently a viscous affair on the front of the
    engine. If when towing you find yourself not going very fast, and this
    fan is playing up and slipping (ie. not turning fast enough), then
    there will be insufficient air flow to cool the car.
    
    It might be worth considering an electric fan (if this is the case),
    but understand it might not cure your problem, which might lie
    elsewhere, as Andrew pointed out, with the actual engine.
    
    Cheers,
    Dan

    Aside from Dan's point, which is a good one, you might like to consider
    flushing the radiator, and replacing the coolant.
    
    Laurie.

I've towed a one-and-a-quarter ton caravan several thousand miles 
in temperatures up to 40C with Volve 740's (similar engine to the 
240) and never seen the temperature gauge go beyong the 'normal' 
segment. I think there is something very wrong with your car, I would 
get the root cause fixed rather than bolting on a fan to cure the 
symptom.

- John.

RE: -1 

John's comments are valid, you have something wrong with your car

Here is what I'd suggest

1. Drain and flush the cooling system
2. replace the thermostat and check to see if Volvo recommend a specific
temperature for towing.
3. check the colour of the sparing plugs to see if your running rich - adjust
carb if necessary.
4. check the fan belt
5. check the fan clutch - if you have one
6. install an oil cooler - most manufacturers recommend installing an oil cooler
on cars used for towing. This is the most expensive thing on the list and you
may not want to do it, but it will increase the life of the engine. If you don't
do it, make sure you change the oil very frequently.

nigel

    I've never heard of a manufacturer recommending the expensive action of
    fitting an oil cooler for towing! Certainly I think this is an extreme
    measure.... find out why it's over heating first, before resorting to
    this, which isn't really a 'cure', more a 'workaround' !
    
    Certainly for the odd bit of towing it shouldn't be necessary, but if
    the car is permanently used to tow trailers/whatever, and the engine
    and cooling system checks out fine, I would say extra water cooling
    capacity was called for more than an oil cooler.
    
    Just my .02.
    
    Cheers,
    Dan$hope_you_sort_it_out,I've_had_fun_with_cooling_systems!

Generally speaking, when you start to put an engine under extra load you *do*
want to keep the oil cool, as well as the water.  If the car had an oil temp
guage I think the driver would have been surprised to see how high it went.

In the US, when you order a towing package, it usually comes with a HD radiator,
an aux oil cooler, and sometimes an auto tranny cooler.  Installing an oil
cooler isn't that hard or expensive and is a good idea if you do a lot of towing.

Dave

Re: -2

Dan,

The oil cooler is not intended to cool the engine, its to cool the oil.
It is expected that the engine will run hotter when towing and the oil cooler is
to prvent the oil from breaking down at the higher temperatures. As I said in
the reply, it will increase the engine life.

nigel

    Re; .5 and flushing the radiator.
    
    This was the first thing that was done when I experienced a gradually
    deteriorating overheating problem on a R5 Turbo and the water appeared
    to be very clean. This did not solve the problem however and other
    things were tried to no avail. At a loss, it was decided to cut off the
    top of the radiator and it was found to be very badly blocked-up.
    
    Mike

    Folks,
    
    Many thanks or the comments.  
    The radiator is showing it's age and has been dosed with Radweld
    so I guess therein may be part of our problem.
    
    The car is due in to the garage for a new exhust on Monday so I'll
    try to get the rad and hoses checked out.
    
    Judy