Thread: low water alarm and overheating

Stupid question: is there sign of coolant in the cabin? wet carpets? Coolant smell?

Or is it actually a leaking hose in the engine bay? $3000 to replace a hose...I'll do it for $2000!

Originally Posted by olbod

Has anyone fitted a low water alarm to the these 4.6's ?
One of Dave's ? Which one ?
Where do you locate the probe on the P38A ?

I have the TM2 Combo so have low water and overheating alarm. Is on a 3.5 but same applies to a 4.6.

For the low water alarm side of the Combo I went for a sensor in the top radiator hose and it works well. You can also go for the top radiator tank or in the overflow tank.

For the temp sensor I bolted mine to one of the inlet manifold bolts in the center of the engine so is measuring the temp of the metal in the engine rather than the water. Temp stays relatively stable when the engine is running while water temp can be all over the place.

Garry

Is the mechanic an LR specialist?

I know what the heater core looks like on a P38A and I find it extremely unlikely that it is the cause of overheating. It's large bore tubing and it would never clog up.

This is one - look at the tube in comparison with my finger (this one was a new one that came with a hole from the factory)




I have fitted a low water alarm to my P38A. It's paert of this: Little Black Box Engine Monitor

Could be as simple as the O rings leaking.

I have recently fitted a low coolant alarm, cost less than $10


see....Low coolant alarm

Bro didn''t mention anything about water in the footwell etc.
But then he didn't know that he had an overheating problem either.
I still dont know how all this came to light.
I havent seen the vehicle during these goings on.
The mechanics are LandroverSpares here in Mackay. Trevor and Graeme Harris are two of the best in the business.
Bro is not going to have the heater repaired as he is sick of pouring money into the thing. Since he has had it, its been one long continious repair job.
In the past I have bought him some bits and pieces from Paul at HardRange to help him keep it going.
A shame because it is a beautiful P38a. Has a Bruce Davis 5 ltr engine.

I will get him one of Daves units the same as mine and place the probe
in the expansion bottle.
Wont bother about a new temp sensor.
I will keep you informed if there is anymore news on the heater.

I think he is wanting to replace it with an L322 RR. I will try to talk him into giving ithe P38 to me !!!

Thank you.

Robert.

I've just re-read what you wrote. Can SOMEONE please tell how the heater matrix puts heat into the cooling system? Please? I must be dumb.

Even if it were clogged, the net effect is nothing. Its an old trick to bypass the heater but that's only done when the heater or hose is leaking. How is this thing causing the car to overheat? It's doing my head in.

Originally Posted by Craig_Keira

I've just re-read what you wrote. Can SOMEONE please tell how the heater matrix puts heat into the cooling system? Please? I must be dumb.

Even if it were clogged, the net effect is nothing. Its an old trick to bypass the heater but that's only done when the heater or hose is leaking. How is this thing causing the car to overheat? It's doing my head in.

The heater core is full flow and allows coolant to circulate around the engine to keep it at an even temperature. What a blocked core does is allow localised hot spots to occur when full power is used and the thermostat is still closed, ie not enough coolant flow to distribute the heat. I identified poor bypass flow as a significant cause of head gasket failure in P76 engines 20 years ago.

Poor bypass flow causes the thermostat to open later than it should, then it gets hit by a rush of hot water, causing the thermostat to rapidly open, then cold coolant rushes in, causing the thermostat to slam shut. Not good for alloy engines.

Originally Posted by olbod

A shame because it is a beautiful P38a. Has a Bruce Davis 5 ltr engine...

... I think he is wanting to replace it with an L322 RR. I will try to talk him into giving ithe P38 to me !!!

Thank you.

Robert.

If it does come to selling and he wont "give" it to you, whatever you do, don't let him trade it. They will give him 3-5K and he may as well put it on ebay with the dealers final offer as a reserve. If he's done a lot to it then list all the repairs and service history and show books/receipts. As you probably already know, having that BD 5.0 will help ensure an enthusiast bids to snap it up. And if it doesn't go up to the reserve you can always grab it in the end by offering him that!