D24t warmup - your experiences?

[Boots]

For those running their D24s in the colder parts of the world, do you find that they take a fair while to produce much heat from the car heater?

Mine produces a bit of warmth after a mile or so but it can be 5 miles or more before you get enough heat to defrost your fingers in front of the vents!

The thing is, a diesel engine doesn't produce much heat unless its being worked (a good thing in terms of efficiency) but as we all know, you shouldn't make the D24 work hard until it's warmed up! Bit of a catch-22.

I believe the thermostat is probably ok as the rad circuit stays cold during warmup and the temp doesn't drop if you leave it idling after warmup...

I think my lump probably has the 'tropical' fan attached as it seems to produce hurricane force winds under all conditions! I wonder if this gale is cooling the lump during warm-up because the viscous clutch is so over-zealous. (It's not seized - you can turn the fan with the motor stopped...) When time and finance allows, I'll be fitting an electric fan and stat to eliminate this potential cause.

During the recent cold snap here in the UK, I've even been thinking of making up a little block with unions to fit into the heater supply pipe and threaded ports for say 4 glow plugs to get some heat into the car in those first arctic 10 mins!

It'd be interesting to hear if anyone else has the same issue with their beastie...

Boots.

[Hecklebone]

Yes, i have the same issue here in Colorado. I use an adhesive block heater for 30-60 min, then start it up and let it run another 30min to get it thouroughly hot before i drive off. If i drive away after running for 5 min, it takes around 10 miles to really warm up, and i avoid WOT. I forget the thermostat temp, but i got the hottest i could.
Also, when i am driving down from the mountains and the engine barely works, the temp needle get burried to the left/cold. So i installed a 2kw marine heater, mine is a 24v system, and that helps a bit...remember, i am in a Pinzgauer. I am also putting a 24v- 110ac inverter so i can run a forced air propane heater in the back.
So, yes, i have the same issues, but due to having a big truck i have room to do odd things. Also, i just finished up retimiing the engine and that might help it burn a little better and get warmer...we will see.
Cheers,
H.

[Boots]

Ah good - glad it's not just me!

Must be nice to have the room to do the mods you mentioned...

I think I'll give the 'glow plug tips poking into a pipe' idea a try then. I think this combined with changing to the electric cooling fan will make enough of a difference for the weather conditions we experience over here.

There will still be some airflow past the block due to roadspeed but it won't be anything like as much as there is now with the loony viscous fan.

It wont be cheap to have the glow plug block machined up but shouldn't be too bad if I can find a suitable blank stainless box to start from. That way, the machine shop would only have to drill and tap the glow plug holes and a couple for the hose unions rather than milling out the cavity for the water flow.

Putting the unit in the feed pipe to the heater matrix should mean that I get the benefit of the hotter water straight away for defrosting the windscreen/fingers. The added heat input should help warm the motor up a bit quicker too. (Not sure the battery/alternator are going to love this plan but they'll just have to put up with it!)

After doing some calculations, I think 6 plugs would be better than 4. I only have 12v available and I think each plug should draw about 10A or so.

Thus with 6 plugs: (12 x 10) x 6 = 720 watts of heating.

This won't make a quick or big dent in 10 litres of coolant but it should be enough to make a difference.

I don't have any experience of using standard plugs to heat liquid and they would almost certainly suffer if the water flow was stopped for some reason but I think they should run pretty cool if the flow is maintained.

Sealing and corrosion wise, if they can withstand combustion pressures they shouldn't leak at cooling system pressures and the anti-corrosion stuff in the antifreeze should mean they won't rust etc.

If I get it all working, I'll post the project up...

Boots.

[745 TurboGreasel]

The 740 heat system feels weak to me regardless, but just for fun, pop your heat control valve off, and have a look through it, I've seen them so restricted coolant will barely go through them.

[Boots]

Thanks 745TG, I will do that. Do you know where it lives? I assume it's under the dash or console somewhere but I haven't been brave enough to look under there yet!

The area is pending an investigation anyway as I want to get my hands-free kit plumbed into the hi-fi and there are a couple of the clips that used to hold the windscreen vents in place that have fallen down into the ducting and need extracting. They have jammed somewhere and are stopping me selecting full hot on the control at the moment, further adding to the lack of available heat!

There is no air-con on this vehicle but if it has a valve for the water flow and the accidental addition of the clips is stopping me selecting full heat, does that mean it has air mix flaps as well as the water flow valve?

Thinking about it, as I write, I suppose the lost clips could just be fouling the cable or lever controlling the water valve - doesn't necessarily mean there are flaps too...

[745 TurboGreasel]

My car doesn't have the auto climate thing,and the control valve lives just behind the injection pump belt cover, and is serviced by a vacuum hose...if you have weak vac, the heat will also be weak.

For the auto climate, I'm not sure.

[ngoma]

That heater coolant valve is normally open at rest. Vacuum closes it. System was designed to flow coolant always thru the heater core, except when A/C set to max. Also, the butterfly flap in the valve, when open, is really only open about 30%.

Obs: Just read your car lacks A/C, so maybe there is no valve?

Test (or replace) the thermostat. Extended warmup times and lack of heat in cool weather point to that.

Could also be clogged heater core. Easy to flush. Careful with the hoses and inlet/outlet stubs.

More remote possibility: slipping impeller on water pump.

[Boots]

No, this model has no vacuum controls at all. The plumbing in the engine bay is just plain pipe right from the motor to the bulkhead.

I've got to do the timing belts soon anyway so I'll be putting a new pump in then. May as well do the stat whilst I'm at it.

I've also got to do under-dash surgery to retrieve the stupid windscreen ducting clips from wherever they've got to inside the heater controls, at some point, so I'll probably give the matrix a good flush out then...

[Nevadan]

Having just acquired my 745 I'm still doing maintenance on it prior to getting it fully drivable. One thing I am going to do is put two block heaters in the freeze plug holes, one near the front and one near the rear, if possible. I understand there may not be room to get them both in, but I will make the attempt. I have one in my 1.6 which will heat that block very good in less than two hours when the temperature is around 15 degrees F. It gets quite cold here in Reno and I often travel in the Sierra mountains so I will be dealing with the warm-up delay.

Another interesting option would be to put a block heater on the radiator side of the thermostat so the fluid in the radiator would also get hot. I haven't looked at how to do it, but it's an idea.

I repaired all the vacuum line leaks so I know the heater control valve is working and I do get hot air from the interior vents. After reading this I will remove the heater control valve and make sure it's not corroded and restricted.