Too hot to tow?

Have a 99 2ltr L series diesel to which I've just fitted a towbar to tow my 1000kg caravan. Tow's absolutely fine at 60mph in 5th until it gets to even the slightest gradient, problem isnt a lack of power it pulls well but the temperature gauge visibly over a period of a minute or so whilst climbing a gradient soars from midway on gauge into the red, if i drop it into 4th and slow to 50mph the temperature almost instantaneouly returns to normal, likewise when the road levels out the temperature will very quickly return to normal.

Checked the water level initially when it happened and topped the expansion tank up about 1/2 inch or so, problem persisted over the next couple hundred miles or so temperature soars but doesnt actually overheat, checked water level after journey and since and is constant, no water contamination of oil.

Is this normal i dont think so, has anyone else any experience of this, thinking for starters the fan isnt working? any other ideas?

C'mon diesel boys, help him out here.

Is there the brown switch for temp sensor like the petrols?


My guess is IRD overheating, lack of oil, or tight VCU, coolant pipe is linked into the IRD.

Run it in 2wd and check oil level, to see if that helps, before thinking about water pump and stat issues

or flow through rad-get it flow tested

Richard B said:

Have a 99 2ltr L series diesel to which I've just fitted a towbar to tow my 1000kg caravan. Tow's absolutely fine at 60mph in 5th until it gets to even the slightest gradient, problem isnt a lack of power it pulls well but the temperature gauge visibly over a period of a minute or so whilst climbing a gradient soars from midway on gauge into the red, if i drop it into 4th and slow to 50mph the temperature almost instantaneouly returns to normal, likewise when the road levels out the temperature will very quickly return to normal.

Checked the water level initially when it happened and topped the expansion tank up about 1/2 inch or so, problem persisted over the next couple hundred miles or so temperature soars but doesnt actually overheat, checked water level after journey and since and is constant, no water contamination of oil.

Is this normal i dont think so, has anyone else any experience of this, thinking for starters the fan isnt working? any other ideas?

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Hi Richard,

No its not normal. My L series tows 1100Kg 22ft caravan at 60MPH and the temperature is rock solid at midway up the gauge.

I hear what NI is saying and it is possible that the final drive is the problem. However, I would say to start with the simple things first. What is the state of your radiator core?

Now I hold up my hand as being responsible for the rain storm we've been getting in the southwest this evening, we're going on holiday next week in the caravan and I washed the Hippo. The rain started soon afterwards.

Now, in the process I addressed a problem I was having with the air conditioning performance. Its working but its not great and its recently been gassed up. Checks showed that the pipe taking the liquid refridgerant to the expansion valve and evaporator matrix was fairly hot. I reasoned that the condenser panel wasn't exchanging heat very well and that would be because it was blocked with dirt.

So, and I can hear the gasps from other seasoned Landy owners so I must stress that you have to be very careful when doing this, I used the pressure washer to flush the radiator, condenser and intercooler cores of dirt. I set the lance on maximum spread and stood back so that the pressure was lost but the water was directed through the matrix. The dirt that came out was quite astonishing. Best news is the air con is now running great.

Check your radiator core to see how clogged it is. Give it a clean anyway and see if that improves the situation.

Good luck,

Dave

I had the same issue when towing a caravan with a L-series (900 kg). If aircon is on it makes matters much worse. It was in the heat of summer as well (38 to 42 degrees C). Also, I was advised to never tow in 5th by a Landy independant specialist. I have narrowed it down to either the thermostat or radiator core that is clogged. I was first going to replace the thermostat, but have since sold the vehicle to a friend. He is going to change the thermostat at the next service, but it is winter here now so we will only see in December or so if the problem is solved.

faureb said:

I had the same issue when towing a caravan with a L-series (900 kg). If aircon is on it makes matters much worse. It was in the heat of summer as well (38 to 42 degrees C). Also, I was advised to never tow in 5th by a Landy independant specialist. I have narrowed it down to either the thermostat or radiator core that is clogged. I was first going to replace the thermostat, but have since sold the vehicle to a friend. He is going to change the thermostat at the next service, but it is winter here now so we will only see in December or so if the problem is solved.

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Interesting!

Has he tried drilling the standard stat ring, you be amazed how much of a difference it makes.

Heres one I did earlier, but it may only need one 3mm hole, anymore and it might overcool with heater on full.

Interesting.... I will pass onto him, maybe worth trying. Thanks for that.