Heater or Thermostat?

[Airgonzo]

With colder weather coming soon I'm thinking I'm going to have problems with the heater in my L400 but I'm not sure from the symptoms whether the problem lies with the heater core or the thermostat. The heater cranks out a respectable amount of heat once engine warms up. Engine temp always stabalizes at just a hair under halfway on the stock temp gauge. It seems to take about 5 min of normal driving for the temps to get to this point. The problem is that engine will not warm up if idling (comes up to just over the C) and then the heater blows really weak and barely warm air. So, first thing in the morning when windshield is fogged up or frosty it's going to be damn near impossible to clear up. Classic catch 22: engine won't heat up enough to start cranking out the heat until I've driven it for a bit but can't see well enough through foggy windshield to go driving.

I'm thinking that the thermostat is probably the culprit but when I've had thermostat problems with vehicles in the past it usually won't warm up at all and that isn't the case here.

Thanks,

Kevin.

[nxski]

Have you tried revving it a bit? Mine won't warm up much until I drive it too. What I do is turn on the air con and put it on defrost with the fan on full blast. It works like a charm!

[thedjjack]

Working like it should. Diesel motor is not making much heat at idle so you need to drive it to get the temperature up.

A block heater and oil pan heater turned on 1 hr prior to starting will help it get warm faster when driving (you could add a space heater inside to pre-heat the interior....

[mac_stang]

My l400 warms up at the rate yours does...and this is the fastest warming up vehicle ive ever owned. That being said, Diesels don't tend to idle very high, and doesn't give much power to run the heater fan at idle in the morning(and your lights and wipers etc)
I have been leaving my windows open a crack over night and this seems to prevent any moisture from settling on the inside of the windshield. I start the van, let in run for about 30 sec, hit the wipers once and drive for about 3 mins and she is pretty warm.

I wouldn't try fixinf something that probably isnt broken.

Brad.

[Airgonzo]

Thanks for the quick responses folks. I sorta thought that might be the case but was just surprised, this being my first diesel, thought it would not warm up at idle. Did a trip up Marriott basin a while back and van was fogged right up. Of course the drive is all downhill for ages and van didn't heat up enough to clear windows till we were nearly in Pemby.

[nxski]

Air conditioning with the temperature set in the red I find is the best way to de-fog without freezing yourself. It cuts down on the water vapor and allows for a much quicker de-frost. You don't need heat to clear your windows (just to remove the water).

[madmazda]

what I do once the snow flies i place card board ( with a few holes in the middle) just in between the radiator and front to slow thew cold air from cooling too much.... works like a hot damn