Heating up

[George130]

Not a real request but a gripe. I drained my coolant yesterday to properly fill it with anti freez/anti boil. I had strait water in the system since an overheating problem. Everything went fine untill coming home today. I shut of the heater matrix and bingo my temperature shot up close to the red. As soon as I removed my foot of the accellerator it started comming back down. Then on the hill near home it started climbing again.
I let it run for a couple of mins before slowly loosening the cap to ease the pressure. I could see the fluid stains around the back of the engine bay.
After returning to the truck tonight I found I had to add 250mls of fluid and also release the bleeder valve and yes fluid leeked out strait away with the engine running.
Most annoying.

[discowhite]

sounds like you have an leak thats causing a vacume.
hot air pockets in the water system will probably be the cause of the
temp gage and the loss/gain of coolant.

find where that leak is.

phil.

[George130]

I did have a leak last time in the radiator but it was inconsistant. I ended up potting a bottle of the seal N go into it. I havn't spotted that leak or a new one yet. I will be putting a bottle of the sealant in tomorrow on my run to work, its an 80k 1 hour trip so should give the stuff the chance to work.

[disconut]

You can't actually shut off the heater matrix water wise in a TD5. The controls just shut off the air flow over the matrix into the cabin.
When you did this, the heat transfer over the heater matrix dropped and you then got a temperature rise.
Old trick when climbing big hills, was to open up the heater and turn on the blower full bore, you then had in effect two radiators to drop the temperature.
I suspect you may have a head gasket problem? Hope i'm wrong.

Trev.

[Redback]

Check the theromstat too the TD5s cooling system is controled by the ECU and has 3 differant systems so to speak in one controlling flow around the engine if the heater is off no flow of coolent to the heater, flow to the heater only happens when the heater is on and revs are more than 1500 RPM so turn heater off and test it. then test the other 2 stages of the system, if you have a manual that would help then you could see how complicated the TD5 cooling system is 8O

Baz.

[disconut]

Guys,
This is the TD5 Disco system. I will check the Defender disc also. It may be different. If so the Disco guys will find this useful.

Coolant is always passing through the heater circuit. Only the air flow is redirected. This is straight off the RAVE disc.If you check the coolant flow schematic it will show you there are no valves in the heater water circuit. The thermostats control the flow on engine warm up and direct water to the heater matrix first.


<span style="color:darkblue">General
The cooling system used on the Diesel engine is a pressure relief by-pass type system which allows coolant to circulate around the engine block and heater circuit when the thermostat is closed. With coolant not passing through the by-pass or the radiator it promotes faster heater warm-up which in turn improves passenger comfort.A coolant pump is mounted on a casting behind the PAS pump and is driven from the PAS pump at crankshaft speed by the auxiliary drive belt. The pump mounting casting connects with passages in the cylinder block and pumps coolant from the radiator through the cylinder block.
A viscous fan is attached to an idler pulley at the front of the engine. The fan is attached to a threaded spigot on the pulley with a left hand threaded nut. The fan draws air through the radiator to assist in cooling when the vehicle is stationary. The fan rotational speed is controlled relative to the running temperature of the engine by a thermostatic
valve regulated by a bi-metallic coil.</span>

<span style="color:darkblue">Heater Matrix
The heater matrix is fitted in the heater assembly inside the passenger compartment. Two pipes pass through the bulkhead into the engine compartment and provide coolant flow to and from the matrix. The pipes from the bulkhead are connected to the matrix, sealed with 'O' rings and clamped with circular rings.
The matrix is constructed from aluminium with two end tanks interconnected with tubes. Aluminium fins are located between the tubes and conduct heat from the hot coolant flowing through the tubes. Air from the heater assembly is warmed as it passes through the matrix fins. The warm air is then distributed in to the passenger compartment as required.

General
The heating and ventilation system controls the temperature and distribution of air supplied to the vehicle interior. The system consists of an air inlet duct, heater assembly, distribution ducts and a control panel. An outlet vent is incorporated at the rear of the cabin. Some diesel models also incorporate a fuel burning heater (FBH) system in the engine coolant supply to the heater assembly.
Fresh or recirculated air flows into the heater assembly from the inlet duct. An electrical variable speed blower in the inlet duct, and/or ram effect, forces the air through the system. Depending on the settings on the control panel, the air is then heated and supplied through the distribution ducts to fascia and floor level outlets.</span>

If you take off your heater matrix outlet hose, turn your heater off, you will pump all of your engine coolant out of the engine.

Trev.

[disconut]

From the Defender RAVE disk.

<span style="color:darkblue">Heater Matrix
The heater matrix is fitted in the heater assembly inside the passenger compartment. Two pipes pass through the bulkhead into the engine compartment and provide coolant flow to and from the matrix. The pipes from the bulkhead are connected to the matrix, sealed with ’O’ rings and clamped with circular rings.
The matrix is constructed from aluminium with two end tanks interconnected with tubes. Aluminium fins are located between the tubes and conduct heat from the hot coolant flowing through the tubes. Air from the heater assembly is warmed as it passes through the matrix fins. The warm air is then distributed in to the passenger compartment as required.
When the engine is running, coolant from the engine is constantly circulated through the heater matrix.</span>

A bit more for interest if you do not have access to a Defender manual.

<span style="color:darkblue">OPERATION

Coolant Flow - Engine Warm Up
During warm up the coolant pump moves fluid through the cylinder block and it emerges from the outlet housing.
From the outlet housing, the warm coolant flow is prevented from flowing through the upper and lower radiators because both thermostats are closed. The coolant is directed into the heater circuit.
Some coolant from the by-pass pipe can pass through small sensing holes in the flow valve. The warm coolant enters a tube in the thermostat housing and surrounds 90% of the thermostat sensitive area.
Cold coolant returning from the radiator bottom hose conducts through 10% of the thermostat sensitive area. In cold ambient temperatures the engine temperature can be raised by up to 10C (50F) to compensate for the heat loss of the 10% exposure to the cold coolant return from the radiator bottom hose.
At engine speeds below 1500 rev/min, the by-pass valve is closed only allowing the small flow through the sensing holes. As the engine speed increases above 1500 rev/min, the greater flow and pressure from pump overcomes the light spring and opens the by-pass flow valve. The flow valve opens to meet the engine’s cooling needs at higher engine speeds and prevents excess pressure in the cooling system.
With both thermostats closed, maximum flow is directed through the heater circuit.
The heater matrix acts as a heat exchanger reducing the coolant temperature as it passes through the matrix.
Coolant emerges from the heater matrix and flows to the fuel cooler ’T’ connection via the heater return hose.
From the fuel cooler the coolant is directed into the coolant pump feed pipe and recirculated around the heater circuit. In this condition the cooling system is operating at maximum heater performance.

Coolant Flow - Engine Hot
As the coolant temperature increases the main thermostat opens. This allows some coolant from the outlet housing to flow through the top hose and into the radiator to be cooled. The hot coolant flows from the left tank in the radiator, along the tubes to the right tank. The air flowing through the fins between the tubes cools the coolant as it passes through the radiator.
A controlled flow of the lower temperature coolant is drawn by the pump and blended with hot coolant from the by-pass and the heater return pipes in the pump feed pipe. The pump then passes this coolant, via the cylinder block, to the oil cooler housing, cooling the engine oil before entering the block to cool the cylinders.
When the fuel temperature increases, the heat from the fuel conducts through the fuel cooler T’ connection and causes the fuel thermostat to open.

On pre EU3 models: Coolant from the cylinder block flows through the oil cooler and, via a pipe and hose, enters the lower radiator; from the lower radiator the coolant flows, via a hose, to the fuel cooler.

On EU3 models: Coolant from the cylinder block flows through the oil cooler to the EGR cooler and then back to the expansion tank.
As the hot fuel cools, travelling slowly forwards through the cooler, it meets the progressively colder coolant travelling in the opposite direction from the lower radiator.</span>
Trev.

[Redback]

This is one reason a heat exchanger for a vehicle shower doesn't seem to work on the Disco TD5 style_emoticons/<#EMO_DIR#>/sad.gif you can't plumb it into anywhere that coolent flows all the time at a constant hot temperature sufficiantly enough to heat the incoming water for a shower, i found this out the hard way, but looking at the way the Defender TD5 works you should be able to plumb a exchanger into the IN & OUT of the heater matrix and it should work, i knew we should of bought a Defender :roll:

Baz.

[disconut]

Put it inline with the heater matrix inlet hose only.
Do not use the inlet and outlet hoses of the heater matrix as you will create a parallel flow circuit and lose efficiency both in the shower and heater.
By cutting into the inlet hose to the heater only, ( series flow all the inlet water through your shower heat exchanger first), then into the heater inlet, you will burn your tender bits! That should do it. :wink:

Trev.

[Redback]

Originally posted by disconut
Put it inline in the heater matrix inlet hose. That should do it. :wink:

Trev.

Tried that, doesn't work as i said above coolent flow to the heater only happens when heater is on and revs are 1500RPM and over.

At the moment (last go at it) it's plumbed into the top radiator hose and into the out of the heater, i've given up after a long time at replumbing it inline, parralell, blah, blah, blah, i don't know what else i can try, looking at the way the cooling system works on the Disco there is knowhere where the coolent flows all the time, very frustrating aspecially knowing how well it worked in our old 4b.

Baz.

[disconut]

:? Your outlet pipe from the heater should be hot with the heater on or off? indicating a constant flow through it.

It will also be a little cooler from the inlet due to some heat loss in the matrix.

Trev.

[Redback]

I think it has something to do with the fact that the Disco has climate control maybe, anyway not the same as the Defender, we are now looking at alternatives.

Wanna buy a helton heat exchanger style_emoticons/<#EMO_DIR#>/biggrin.gif

Baz.

[George130]

Thanks for the info. Last time this happened I read up on the workshop manual and came to the conclusion that my leak was on the third circuit used for the cooling of the fuel. That is it needs to get everything hot before it will leak. The system passed as pressure test and there is definatly no coolant in the oil or oil in the coolant.

Toped it up and once it was warn added half a bottle of stop n go sealant this morning. Not even a hicup on the temp guage now same as last time.
I havn't turned of the heater yet though.