Restoration-Mini

Technical Forums => Maintenance and Modifications => Topic started by: Dmulder on March 24, 2016, 11:06:43 AM

Title: Defrost issues
Post by: Dmulder on March 24, 2016, 11:06:43 AM
For those of you who drive in conditions requiring defrost/de mister how do you make yours work well enough to actually do any good. The last few days I feel as if I'm driving around in fog. The fan works. However it seems to push more air when I have it selected to car and less air when selected to screen. Also how to you get the car to make heat. Either my valve is broken or my little motor just doesn't make much heat. I feel like a Popsicle in a fog.
Title: Re: Defrost issues
Post by: LilDrunkenSmurf on March 24, 2016, 12:30:59 PM
It's generally pretty terrible. I have to leave it running ~30 minutes on full blast, before the car comes up from "3 layers of clothing".

I've learned to live with it, and crack the windows.
Title: Re: Defrost issues
Post by: 94touring on March 24, 2016, 12:54:22 PM
Mine works pretty well.  May want to flush the heater core and verify your valve is open.  You can also go with a hotter t-stat for the winter to bring temps up.
Title: Re: Defrost issues
Post by: tmsmini on March 24, 2016, 12:55:44 PM
If this is a MK I - MK III heater then the rubber foam "gaskets" may be leaking and the hot air is going every where. It is also possible the demister ducts are leaking. Actually the heater can do a pretty good job, but if the engine is not getting warm enough, it can be an issue. The thermostat may be stuck open as well. What is the outside temp in Michigan right now?

I have added the later type dual impeller fans to the early boxes and it helps a little bit.
Title: Re: Defrost issues
Post by: Dmulder on March 24, 2016, 01:02:12 PM
30-35 and rainy. Even my 08 town and country struggles to keep the Windows 100% clean
Title: Re: Defrost issues
Post by: Dmulder on March 24, 2016, 01:39:02 PM
I think I'm going to check and make sure the valve isn't broken and try cleaning the heater core. I have checked the hoses going up to the vents but will check again along with checking the foam gaskets. I've contemplated cutting down the air inlet to the radiator to block some cold air out in winter. Would that be okay or should I just look for a hotter thermostat. After installing my hills and fixing the heater my next project is a new front window seal. Nothing like two solid days of cats and dog rain to let you know the fro t deal is bad.
Title: Re: Defrost issues
Post by: tmsmini on March 24, 2016, 01:40:28 PM
With that range of temperatures I would definitely be using a thermostat that opens after 180
Title: Re: Defrost issues
Post by: LilDrunkenSmurf on March 24, 2016, 01:58:40 PM
Mine is terrible for getting up to temp. Mind you when I'm having these issues, it's usually -10*C.
Title: Re: Defrost issues
Post by: Dmulder on March 24, 2016, 03:10:47 PM
While I'm at it. Instead of starting another thread will I need a cone compressor to install my hi los?  I still can't find my crazy manual so a new one is on order.
Title: Re: Defrost issues
Post by: MiniDave on March 24, 2016, 03:12:38 PM
Buzz worked really well after I replaced the leaking haeter core, installed new foam around the core and replaced the foam gasket for the door......however, about the only part of me that got warm on a really cold day was my foot - the one right next to the heater!   ;D
Title: Re: Defrost issues
Post by: 94touring on March 24, 2016, 03:36:10 PM
Quote from: Dmulder on March 24, 2016, 03:10:47 PM
While I'm at it. Instead of starting another thread will I need a cone compressor to install my hi los?  I still can't find my crazy manual so a new one is on order.

Cut out the old trumpets and you won't.  Much easier imo.
Title: Re: Defrost issues
Post by: Spitz on March 29, 2016, 07:42:01 PM
A classic MINI heater works great if everything is in working order.....including defrost

Do check that you have the right thermostat.
If your core or hose has a slight leak...this will fog you up also.
Also, do double check your valve is completely open.  Not sure which valve you have.....if on the right side of the head your knob goes all the way in to be open.  If it's the later plastic in-line valve, knob needs to be pulled out for heat.
Title: Re: Defrost issues
Post by: John Gervais on March 30, 2016, 03:20:16 AM
Quote from: 94touring on March 24, 2016, 03:36:10 PM
Quote from: Dmulder on March 24, 2016, 03:10:47 PM
While I'm at it. Instead of starting another thread will I need a cone compressor to install my hi los?  I still can't find my crazy manual so a new one is on order.

Cut out the old trumpets and you won't.  Much easier imo.

Ah, yes, but it also helps to use the cone compressor to hold the new cones at the top of the tower when re-installing the HiLo's and wobbly knuckle joints.


When I installed a new heater core in mine, I found some self-adhesive foam (noise insulating type, it was too thick, so I had to trim it down) and replaced the decayed strips at the flap-diverter.  The old heater core was wrapped/packed/sealed with a wool-like material, so I bought a wool placemat at the kitchen store and packed the new core as the old one.  I also used some metal-type duct sealing tape around where the flexi-hose joins the demister nozzles.

My biggest issue now is that the speedometer fogs up in cold, humid weather, so I should look into a new O-ring for that.