dashboard rattle GU III Patrol STL

thanks for your help, but i think it might be something different. mine sounds like a thin metal wire is banging onto something.

Hi Robin

What did you find when investigating why the air entering the car via the vents is hotter than the outside air?

Never found the cause with my old Patrol and the new one does the same. Seems more noticeable at lower speeds

Patrols and other modern cars don’t appear to have a valve closing off the fluid to the heater element. The hot coolant circulates through the system even when the heater is off.

Always wondered if it was the heater partially heating the incoming air or whether the fresh air pick up was sucking hot air from the engine bay.

Be interested to know what you found out. I tolerated it on the last patrol and the new one does the same, this time I am going to fix it.

Regards
Spinifex

I had the same hot air problem as you, i fixed it by putting a heater valve in the inlet side of the heater pipe under the bonnet.

Hi Guys

Unfortunately Spinnifex I could not come up with a proper fix and I did try hard.

I first thought , that like Slush , that it was caused by an improperly closing water valve, as a little bit is meant to always flow. I fitted and still have an inline 19mm Nylex tap to completely turn off water , and this proved that this was not the problem.

I felt It could have been , heat straight thru the firewall , and fitted aluminium backed insulation across it and this did not stop it.

I felt it was hot air under the bonnet coming up into the vents (There is an air path via the bonnet hinges into vents) , later 2003 models have a block there, and I blocked mine which I think made the tinnest difference but the main problem stayed.

I thought the problem may have been hot air coming into the vents via the seal at the back of the bonnet. I taped up the junction fully , and this did not stop the problem.

I have temperature sensors in the air outlet pipe into the cabin and on the winch on the front of the car.

From these can say what perhaps is obvious in that a huge volumne of hot air is generated by the car it comes under the back of the front wheels and cascades around the bonnet and some goes into the air intake.

This makes the problems a lot worse when stationary. I measure around 7-9c
warmer air into the car when stopped.
as you drive faster , the air from engine is forced back and you get more fresh frontal air, but this air is still 3-4c warmer than outside air.

I have identified a secondary mechanism , and that if can is in even partially
warm sun the the internal plastic air distribution ducting gets hot and warm the cooler incoming air and this effect takes many minutes to dissipate.

A third mechanism is that the fan itself delivers roughly 1c of heat into the air.

The only practical advice I can offer is that the higher the fan speed the lower the temperature rise, and to get a dash cover.

A real positive step would be to insulate the ducting however this is beyond me,
and I just leave the windows down longer before I go for the air-con.

I once had a broken windscreen, and got a standard one instead of the more expensive protector one with internal heat reflecting film

Robin Miller

Robbin, I understand what you are saying about all the heat from air ducts, fan motor, ect. but i nutted this out over a long time. I was driving to Melbourne one night which i do regularly non stop, but this time i stopped about midnight and found the air was still quite warm coming out the vents compared to out side temp. when i finished what i had to do in Melbourne about ten am that morning i went to the auto barn on the way out and fitted a heater fluid switch for the return trip home. this is how i noticed the major change in air temp from the vents.may be a few degrees higher than out side but not like it was.

Leaking past the valve does happen a bit , or more often , bad adjustment so that it does close properly , thats why one of the first steps I took Slush was to test car with no heater water flow. Although even with water flow , the air flap has no not seal properly so that air actually goes thru core.

Glad you fixed your main problem , driving home last night 33c and air vent temp in my car was 38c , don't like that.

Robin Miller

Legend. Have been looking for 2 months.

Cheers