ford mondeo tddi - jerks with aircon on.

Honest John Back Room » Technical matters
View Threaded
Tue 8 Aug 2006 23:41
ford mondeo tddi - jerks with aircon on. - blondewivabrain
is there anyone who can help, i have a ford mondeo 2.0 tddi y reg 2001i use this as a taxi hence mileage being 205,460, my problem is when i use the aircon after about 20 miles the car starts to jerk then i lose power and the engine cuts out, this happened today on the outside lane on the motorway, after switching off and leaving the car for about 40 mins it starts first time, this problem does not happen if i dont use the air con , many thanks claire
Reply | Report as offensive | Link
Wed 9 Aug 2006 15:11
ford mondeo tddi - jerks with aircon on. - Saltrampen
Not an air con expert - but sounds like a stiff air con compressor pulley causing its drive belt to jam and strain engine possibly? Perhaps bearings are worn in this pulley causing them to expand after a while and drag?
I would have thought that a diesel engine had enough power just to slip or break the belt so I am not 100% sure this could happen.

Whether I am right or wrong aircon faults are best looked at by a dealer or an aircon specialist...
Hopefully an aircon expert on the forum may know more?

Reply | Report as offensive | Link
Wed 9 Aug 2006 15:47
ford mondeo tddi - jerks with aircon on. - adverse camber
I would be thinking in terms of something on the electrcal side overheating and making or breaking a connection. Dont know the mondeo though.

does it take 40 mins or is that just how long you happened to leave it?

it takes a lot to stall a diesel. can you replicate it under no load? run around for 15 mins then sit and idle for a while?

how repeatable is it?
Reply | Report as offensive | Link
Wed 9 Aug 2006 22:19
ford mondeo tddi - jerks with aircon on. - blondewivabrain
it takes about 40 mins before the damm car will let me restart it again, it has happened again today, the strange thing is when im just driving round the town its perfect , but as soon as i get on the motorways it happens, it starts to jerk, loses power then conks out, which is frightening when you are in the outside lane on the motorway. many thanks for all the replys,
Reply | Report as offensive | Link
Wed 9 Aug 2006 22:55
ford mondeo tddi - jerks with aircon on. - Armitage Shanks {p}
Now that the weather is a bit cooler why not drive it around with the a/c off and see if the fault still happens?
Reply | Report as offensive | Link
Thu 10 Aug 2006 12:06
ford mondeo tddi - jerks with aircon on. - blondewivabrain
the car drives perfectly without the air con, so now i just drive with the windows down and hair like worzel gummidge !!! lol
Reply | Report as offensive | Link
Thu 10 Aug 2006 12:16
ford mondeo tddi - jerks with aircon on. - robcars
At least we should all be able to recognise you then?
Reply | Report as offensive | Link
Thu 17 Aug 2006 21:52
ford mondeo tddi - jerks with aircon on. - megrandad
ok air compressor is siezing up suggest new compressor or not to use it ??? normaly all cars will suffer a degree of power loss when air con switched on as this takes on average about 10 bhp of your car SO BE WARNED [megrandad]
Reply | Report as offensive | Link
Thu 17 Aug 2006 21:56
ford mondeo tddi - jerks with aircon on. - Armitage Shanks {p}
There is no air compressor in an airconditioning system! Not in mine anyway!
Reply | Report as offensive | Link
Thu 17 Aug 2006 23:51
ford mondeo tddi - jerks with aircon on. - Armitage Shanks {p}
Nothing like 10 bhp used!

"Department of Transport sponsored some research into fuel economy on trucks which included the use of AC. This technical evaluation was done by BTAC/IRTE (British Transport Advisory Committee/Institute of Road Transport Engineers) at the MIRA test track at Nuneaton at the highest speed lorries are able to do with their speed limiters (56mph). At this relatively low speed the effects of an open window are nothing like so serious as they would be at 70 mph, but even so the effect on fuel consumption of the AC switched off and the window open was to increase the consumption by 7% - quite a staggering increase for such a moderate speed. With the windows closed and with the AC switched on, to quote the starchy language of the official report, ?the consolidated data suggest that air conditioning has a minimal affect on fuel consumption?."
Reply | Report as offensive | Link
Fri 18 Aug 2006 01:04
ford mondeo tddi - jerks with aircon on. - Aprilia
I suspect he meant air-con compressor - its actually a gas compressor.

I think most AC takes a fair few horsepower. Maybe not 10bhp, but I wouldn't be surprised at 5hp. The modern variable displacement types are a lot more efficient though, I think.
Reply | Report as offensive | Link