Bongo overheating when running air conditioning

[winchman]

Glad you are sorted, why wasnt the fan working?

[Matt&JoyBongling]

I have a similar problem. I'm in France where it is regularly 35oC or so. When driving along the flat with the A/C on, all is generally OK. When going up hill, the mason adjusted temp gauge shoots up to just a few degrees less than max. The only way I can cool it when I am travelling is to turn the heating (front and rear) to max and turn off the AC. The temp gauge returns to normal. It will shoot up to almost max if I put the A/C on again and try going up hill.

I have a hi / lo coolant alarms fitted and they have not reported any water level problems.

Any suggestions on what to look for as a fault and how fix & test it before we start out journey home?

[Northern Bongolow]

the next time you get it really hot, stop, with the engine running, let it tick over until the main front fans cut in, it may take a while, then watch the temp gauge drop. if the fans are not cutting in you may have a fault, but it sounds like everything is working ok. the front and rear heaters are best left off in my opinion as you are removing heat from the system, but this is encouraging the stat to close when you really want it to open. the drop you are seeing is probably the front fans cutting in and not as a result of the heaters being on.

[Matt&JoyBongling]

Thanks. I have turned the heaters on as I did not want the temp gauge to read so high for long. If I have a mason alarm, how far can I let the temp gauge go? I have not let it go to max but it is not far off. It does not seem to go further than a few degrees off max but it is a long way off normal. I don't want it to get to max and have not left it at high for more than a few seconds - maybe 20 at most. It cools down to near normal within about 1 min of the heaters being turned on.

[Northern Bongolow]

the mason modified gauge should read just before the hot line, (just at the ar*e twitching point). when the firrst stage rad fans are triggered, then you still have the fast speed fans to come on. so dont panic, give it a go.

[Matt&JoyBongling]

the mason modified gauge should read just before the hot line, (just at the ar*e twitching point)

The gauge has not got to the hot line - but, as you so correctly identified, it has got to the ar*e twitching point several times. It has never got to this stage before although I had thought we had done similar trips in similar temperatures before.

Do you have any idea at what point I'm likely to cause terminal damage to the engine? Will it die if the gauge stays at the thin hot line for several minutes or does it need to get to the thick hot block before damage occurs? How quickly / soon should the quick fans come on and any idea why it is getting so hot now without the fans coming on?

With thanks from an ar*s twitching driver ...

[Northern Bongolow]

look for a good post in the search area by widdowson2008, he has identified the switching temps of the fans.
the problem arises with how you are measuring that temp, how accurate is your gauge/s,sender etc.
you need to establish if they are working or not. the way i do it is take it to the twitching point, then stop the engine for 30 seconds, this allows the heat to build up in the head, then switch the engine back on, or at least the ignition and the fans usually come on.

the temp gauge is damped so by the time it registers hot theres not much you can do big twitch.

[teenmal]

Hi Matt&JoyBongling,

What setting are you using on your Mason alarm?

Cheers.

[Matt&JoyBongling]

Thanks guys. I'll look for widdowson2008's post.

The Mason alarm is set to 5. I get lots of squeaks when the temp gets towards high - I have not let it get to the continuous beep.

[Matt&JoyBongling]

Am I right in thinking that the Mason alarm setting determines the temperature at which the alarm is set off and doesn't determine how responsive the gauge is? I believe that the mason alarm makes the temp gauge more responsive. The dial adjusts when the alarm goes off.

[mikexgough]

never had any issues with overheating with air con running as engine fans are fired up all the time, in fact my fans ran for the first time in 3 years last Friday.....and not because of the A/C.

I was in a traffic queue in Malton Yorkshire..... got to just before the black line by the red mark and away they went..... cooled to 11:30 on the gauge as usual. On the fast run home the gauge was at the usual 11:30 and 12:00 when pulled off to come into the town, before dropping to normal.

[widdowson2008]

Thanks guys. I'll look for widdowson2008's post.

Is this the one Ady?
http://www.igmaynard.co.uk/bongo/forum/ ... hilit=fans

[Northern Bongolow]

thats the one steve, thanks.

[mikexgough]

forgot to add..... not using a Denso sensor.... still a grey top but not a Denso....
The same sensor is used on Jap motorbikes too....