300TDi Heating

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taazzukcb

Active Member
Posts
126
Hi All,

I know this has been covered several times and I have indeed read most of the similar thread I can find, but they normally result in a similar answer of Thermostat. I've now tried 2 without much change.

Basically the 300tdi never seems to get warmed up properly and my heaters never get chance to chuck any warm air out which is a pain in this weather ... Would certainly be nice to have some warm air!

I go 26 miles to work and the temp gauge is only 4mm or so above the cold blob. So only just out of cold.

It gets to this point reasonably quickly, within say 3-4 miles, but then wont move from there. Every now and again it'll go up to the proper mid way point and normally in my excitement, I then turn the heaters on, hoping for some nice warm air, for it to then decide to drop right back down again.

Having been a bike only guy for the past 7 years I'm also a stipler for making sure an engine is warm, but I just cant get the Defender to warm up and it does worry me as I like to be sure it's getting warmed up.

I've changed the stat twice with no change. I re-built the head 3000 miles ago or so and it got a new water pump at that point to (cant remember, but it may of been a britpart), obviously fresh coolant.

Radiator is solid and was nicely flushed.

Pretty sure it's fully bled up etc ...

Just cant get it to get warm!

Also, I dont run a fan. Have an electric Mondeo fan on it which isn't wired up yet, so it's not a stuck viscous etc.

Any body have any suggestions???

Kind regards to all.
 
2 things spring to mind, is it ACTUALLY not warming up, ie have you checked the temp on the engine itself as apposed to relying on the gauge.
id do that first, then check the cables for the heater are adjusted properly, the matrix is in good order and sealed properly.
 
Pretty sure the gauge is accurate. I have considered this and checked all connections and I gave the temp sensor a check over and all seemed to be giving the right signals out.

Like I say, it some times (not lately) rises up to the middle.

Also pretty sure the cables are ok ... If I swipe the left side all the way down, I have an extra click and I can get the full mild hurricane mode that seems to make more noise than anything else, but it does chuck a decent amount of air out ... It's just cold!

Heater box is nice an sealed.

Like I say, on the odd occasion that the needle goes properly up to half way and sticks there, I can then put the heaters on and it will give me warm air. I just cant get it up there or to stay there very often!

Thanks for the thoughts though! I will give them all another going over, but think they're all ok!
 
Does your top heater hose get hot to the touch, whilst the bottom one remains relatively cool?

Is there debris in your air feed from the wing to the heater box that needs cleaning out?

If you short the bit of wire to the block, the one that goes to the temp sender to the gauge, does it swing right over to 'hot'? If it doesn't it could be that your sender isn't working properly.

Have you bled the system through the heater? If you haven't you could be air locked, which could affect the entire cooling system.

Let me know when you have checked these. ;) ;)
 
mine stopped blowing hot air and was just a matter of disconnecting the two heater matrix hoses, sticking the garden hose on full into each twice for a minute or two and all was sorted, build of muck in the matrix i suppose, only had to do this once a year

both hoses to the matrix are hot, but suppose its no good if the matrix if full up with no hot ater but crap

must admit when i stop for a cuppa and have the engine running the temp guage goes down and cold air again, but probably the fan sticking like you said ealier
 
Does your top heater hose get hot to the touch, whilst the bottom one remains relatively cool?

Will check this one at Lunch!

Is there debris in your air feed from the wing to the heater box that needs cleaning out?

Air feed is nice an clear!

If you short the bit of wire to the block, the one that goes to the temp sender to the gauge, does it swing right over to 'hot'? If it doesn't it could be that your sender isn't working properly.

Will try and give this a go to! Must have a paperclip around here somewhere I can use to short it!

Have you bled the system through the heater? If you haven't you could be air locked, which could affect the entire cooling system.

Now this is interesting ... I bled the main system very very carefully, but never thought about the heater bit. I first filled through the Rad plug, then through the upper plug near the oil filler cap (cant remember what the square block section is called), then once that seemed clear of air bubbles and topped up, I never thought about the heater.

How would I go about this? Just to be sure? Is it the method r06ert suggested?

Is the the pipe that runs across the top of the head?

Let me know when you have checked these. ;) ;)

Please see red :).
 
fan sticking or not shouldn't really make much difference, when the waters cooled, the stat closes, so no water running round rad.
Fan is there more for slow moving traffic, or when your stood still, once over about 15mph, the airflow through the rad is more than the fan pulls anyway.
 
I know you said you have fitted a new thermostat, but are you sure it's actually working?

Also, when the engine is running just undo that plastic bung on the top of the thermostat housing, see if there is any water in there.
 
I know you said you have fitted a new thermostat, but are you sure it's actually working?

Also, when the engine is running just undo that plastic bung on the top of the thermostat housing, see if there is any water in there.

Both new thermostats work fine doing the usual trick. The old thermostat was also fine based on the same test, but replaced anyway just in case ... then again for a third stat :p!

They're cheap so thought I'd be sure!
 
Please see red :).
If you undo the upper hose jubilee clip on the heater and then with your thumb on the pipe, top up your reservoir until water comes out of the heater.

Replace the pipe. Job done:D

The other thing to check is that your earth is good to the block, as a poor earth will give you a much lower reading at the gauge ;)
 
Right quick play.

Just took the higher of the 2 pipes off the heater matrix, the front one which sits ever so slightly higher of the 2. No liquid in the rubber pipe. Nothing out of the matrix.

Started her up and go some pumping out of the matrix, so it was nicely pouring right on the fuse box :p ... Stuck the pipe back on. Coolant was looking clean that was coming through the matrix. Looked a bit green and I'm sure I went standard blue after flushing when the head was done!

I shorted the gauge to the block by using a scren into the plug female, then sat on the block ... Straight up to well past hot! So gauge must be ok?

Not had chance to go for a drive, so can comment on heat as just sitting there for 10 mins didn't get her very warm.

Hows this all sound?
 
It sounds as though your gauge is OK.

You will need to run the engine for a bit more than 10 minutes though, as you need it to get up to full running temperature.

Let me know how she is once you have given her a good run.
 
It sounds as though your gauge is OK.

You will need to run the engine for a bit more than 10 minutes though, as you need it to get up to full running temperature.

Let me know how she is once you have given her a good run.

Yep, I knew 10 mins wouldn't be enough, but it did start to rise out of cold, but just didn't have chance to give it a run before I ran out of time.

Will report back when I do the home run!

On a side note, I was going to get a sender ordered anyway as backup, but cant work out if Black or Green is the correct one for a Defender 300tdi ... different forums report it both ways around!
 
Right, reporting back.

On the journey home, within 2-3 miles the needle went up to it's usual position. At this point in my journey the roads get interesting so stop paying attention for a mile or 2, the noticed I was up to half way. A further mile I was about to try the heaters but it had dropped down again ...

Again, little further on, needle went up to half ... then a few seconds later dropped back down to it's normal spot!

I thought sod it and turned the heaters on. A little cool air later and I started to get some reasonably warm air coming through. Not exceptionally hot, but then I don't know how hot they normally get as I've not felt a functional system :p!
20 miles later it stayed chucking out some reasonably warm air.

Got home and manoeuvred into position, then shut the heater off and temp shot off up to mid way ... Very odd ...

Turned the heater back on again and it dropped back down ... turned off again but this time it didn't move back up (obviously a decent pause in between each movement).

Is my sensor duff?
 
If your gauge shows a drop when the heater is running it means that the system is taking some of the heat away from the engine, and that's what it should be doing.

Have you got the air flap on your heater set up, so that it is directing the warm air into cabin?

On the engine side of the heater box you will find a lever, which is actuated by the left-hand (fan) slider. Make sure that both it and the cable control are free and moves when you move the slider.

Your sensor might or might not be duff, so let's go one step at a time :D
 
All the heater levers and work as they should I believe.

Left side - Moves up and down, Up is of, middle section is a small amount of air, all the way down to the bottom, there's an extra positive click and then the heater blower starts to sound like a hurricane. This is the setting I've left it on last night and this morning (After giving the motor a chance to warm up for a couple miles). Muffles the sound of the straight through exhaust at least :p!

Sat a rag on the inlet yesterday for a few seconds when playing around and there's a good amount of suction there.

Right side - Hot and Cold does exactly that, which ever way around it is, one way makes it hot, one way makes it cold (well, reasonably warm and reasonably cold :p).

Other Right side - I can move the air flow from the feet outlet, to the windscreen outlet. Windscreen outlet isn't overly powerful and pushes a bit out through the feet, so maybe a tweak here.

EDIT: When the gauge drops after putting the heaters on, should it eventually come back up again? Or does it stay down on the lower reading? Because mine stayed down, but did continue to throw out some reasonably warm air all the way home last night and all the way in this morning.
 
under the bonnet, on the top of the heater housing, make sure the hot/cold selection lever is moving the lever on the top of the box to its extent of travel. its common for them to get loose/stretch and not pull it to the full "hot" position.
 
how fast was the gauge going up and down?

if you are into buying bits and bobs, then go buy an infrared thermometer for around a tenner. then when warmed up start shooting and see what temperature the engine/ pipes/matrix really is.
 
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