Cold heater!!

[Guest]

Picked up my first maestro today, deisel turbo.

car done 500 miles today, however the heater was stone cold, never missed a beat otherwise tho

guy i got it from said it was blowing not very cold air for the first 200, but the 300 i done it was stone cold

any suggestions ?

[E_T_V]

Worth trying to flush out the heater matrix and the pipe on the manifold as they get clogged. However before doing this try this:

With a cold engine open the expansion cap to release any residual pressure and retighten it
Start the engine.
Allow it to idle for 30 seconds or so then acclerate the engine hard several times.
Then allow the engine to idle for a few seconds and then turn the engine off.
Release the expansion cap again listening carefully. Any release of pressure signifies head gasket failure.

[Captain Slow]

Yes. Were you trying to get hot air out of the vents on the dashboard? If so, forget it - they're fresh air vents.

Other things I'd suggest are taking a look at your thermostat and possibly your fuel/air mixture (If it's not warming up, neither will the heater)

[countrydude]

Listening for that gurgle of hgf it is a sad day when that noise reappears!

Sam it is more the nature of a direct injection diesel that doesn't make a huge amount of heat. The heater on a diesel engine can be lacking from a petrol. Also advising someone to up the fueling on a car suspected of hgf is not the best advice.

[Guest]

Bit of an update!

There seems to be some heat when the dial is set to feet and also windscreen, not roasting hot, but as countrydude has suggested this is probably because its a diesel.

The vertical vents above the radio just blow cold air tho. so is this normal ?

[G Force]

The vertical vents above the radio just blow cold air tho. so is this normal ?

Yes thats normal, the centre and side vents are fresh air only but they can be closed this weather. The heat is from screen & floor vents. You won't be the first or last new to MM,M cars to not realise this so don't worry.

[Guest]

Thanks for the replys, that is good news, i read somewhere it could be a headgasket, but thankfully not!!

Shame we had to drive 300 miles with no heater yesterday tho

[E_T_V]

Haha yes good news. The centre face level vents only supply cold air (as denoted by a little blue marker next to them), but many people don't realise as it is a little unusual. Only the windscreen and feet vents supply hot air.

The diesels don't produce a lot of heat though!

[Guest]

The temp gauge on the dash board isnt working, it moves when you tuen the car on, but not off the cold position, would this be a faulty thermostat perhaps?

driving into work this morning about 15 miles of b roads, the heater was hot, but after it had been on for a while it was cold again, turned off for a few miles it was hot again!! Is this just normality in a Diesel maestro?

[E_T_V]

Sounds like poor coolant flow through the matrix. The pipe on the manifold gets clogged as does the matrix itself so this could be worth a flush.

If the gauge eventually warms up whilst in traffic but falls when on the move then this indicates it is faulty and needs replacing (if there is one in there!).

[Guest]

Sounds like poor coolant flow through the matrix. The pipe on the manifold gets clogged as does the matrix itself so this could be worth a flush.

If the gauge eventually warms up whilst in traffic but falls when on the move then this indicates it is faulty and needs replacing (if there is one in there!).

Was planning on a flush and new anti-freeze this weekend.

The temp gauge doesnt move off cold, when i say it moves, i mean you its just moving fromm being off, its not reading anything!!! would this be due to thermostat, temperature sensor/sender or the gauge? any suggestions before i start throwing money at stuff and discovering its fine!

[countrydude]

you have 2 sensors on the thermostat housing, check the single spaded sensor as this is for the dash. It could be faulty and need replacing or it could be making a poor connection.

[PeterMGman]

Cold Heater

I'll give odds of ten to one that it's the thermostat, stuck in the 'open' position.
That's assuming that you're topped up with coolant, of course.
As this is easy to check, do this before you look for other possible causes.
With the engine cold start up and let it run while you feel the top of the thermostat housing. This should stay cold as the engine is warming up because the thermostat stops the water flow. If it starts to get warm early on then your thermostat is stuck open (ie is broken).
A new thermostat is a fiver or so and you can use an 88C though some folk like a 92C for cold winter months.
I hope this helps - let us know how you get on.
Best wishes,
Peter

[Guest]

Changed the thermostat at the weekend, and the temp gauge now works better.

on a dual carrageway the temp gauge rose to the middle, however on the way to work, 14 miles of A roads, the needle never moved much off the cold. heater wasnt much warmer either, guess this is just normal for a Diesel

[countrydude]

as said above i'd check it is a 92 degree stat as that will help with the temperature. I'd say 14 miles of a road driving should be plenty to get some heat going. I'd try switching the pipes around on the matrix. They will be stuck solid but undoing the clamps and then twisting with plumbers pipe pliers will unfasten them. If you undo and fold the pipes back on themselves quickly you can save draining the system. Get a couple of fresh jubilee clips at the ready just in case.

This will reverse flush the matrix in a constant and steady fashion. I'd just keep an eye on the coolant becoming murky from the blockage/sludge buildup in the matrix if successful.