Volvo V40 GDI overheating - mystery cause.

Certainly running a Volvo white block without a 'stat or with a right-royally shafted one will cause the MIL to come on- the ECU knows how long it should take the engine to reach operating temperature based on ambient, and drive style, and if it doesnt, will pop on the lamp.

The gauge is also driven by the ECU and has only 3 static positions - cold, normal, and overheating...

Tim..

messagenews:Xns9947D596838B4stuartggraydslpipexc@216.196.109.145...

Two rather long additions to this thread by me via Google groups have not turned up, so I'll try again...

First of all, to reply to this message, the engine is not a traditional Volvo engine - as far as I can tell, it is a Mitsubishi GDi, so knowledge of Volvo blocks may not be relevant. The temperature gauge is definitely not tri-state, but continuously variable.

Secondly:

After a long run up the M40, the temperature gauge climbed up to the border of the red zone several times - including the hill up from the Watlington turn-off to the Chiltern gap. Turning the heater on rapidly allowed the indicated coolant temperature to drop.

Checking the radiator and the user manual tells me a couple of things:

1) As indicated in the owner's manual, the radiator is a single unit wherein one side (apparently) is for engine cooling, and the other side is for the air-con. Each side has a fan. Both fans work. The actual circulation of coolant is not obvious.

2) After the long run, the radiator is not uniformly warm. The top was warmer than the bottom, and one side was warmer than the other. One was cool enough for me to rest my knuckles against indefinitely, the other was to warm to do this - however I suspect the hot side is the side used for the air-con, which I had had turned off. There were no obvious cold patches.

The radiator currently in the car is a Nissens 65543A. The engine, being a GDi is either a B4184SM or B4184SJ and the Nissens website shows two possible radiators for these engine variants: 65543A or

65559A. I can't find the engine designation on the engine, but the latest documentation from the garage claims it is a B4184SJ. The Nissens website says the appropriate model from their range is 65559A, which is not the one installed in the car. I'm not happy. The drawings on the Nissens website look identical, but there must be _some_ reason why there are two variants.

I'll report back once I get the time to get this sorted.

Thanks for all the advice.

Sid

messagenews:Xns9947D596838B4stuartggraydslpipexc@216.196.109.145...

Two rather long additions to this thread by me via Google groups have not turned up, so I'll try again...

First of all, to reply to this message, the engine is not a traditional Volvo engine - as far as I can tell, it is a Mitsubishi GDi, so knowledge of Volvo blocks may not be relevant. The temperature gauge is definitely not tri-state, but continuously variable.

Secondly:

After a long run up the M40, the temperature gauge climbed up to the border of the red zone several times - including the hill up from the Watlington turn-off to the Chiltern gap. Turning the heater on rapidly allowed the indicated coolant temperature to drop.

Checking the radiator and the user manual tells me a couple of things:

1) As indicated in the owner's manual, the radiator is a single unit wherein one side (apparently) is for engine cooling, and the other side is for the air-con. Each side has a fan. Both fans work. The actual circulation of coolant is not obvious.

2) After the long run, the radiator is not uniformly warm. The top was warmer than the bottom, and one side was warmer than the other. One was cool enough for me to rest my knuckles against indefinitely, the other was to warm to do this - however I suspect the hot side is the side used for the air-con, which I had had turned off. There were no obvious cold patches.

The radiator currently in the car is a Nissens 65543A. The engine, being a GDi is either a B4184SM or B4184SJ and the Nissens website shows two possible radiators for these engine variants: 65543A or

65559A. I can't find the engine designation on the engine, but the latest documentation from the garage claims it is a B4184SJ. The Nissens website says the appropriate model from their range is 65559A, which is not the one installed in the car. I'm not happy. The drawings on the Nissens website look identical, but there must be _some_ reason why there are two variants.

I'll report back once I get the time to get this sorted.

Thanks for all the advice.

Sid

++++++++++++++++++++++++++ As promised, an update.

The behaviour got worse, with overheating occurring even at 50 mph, meanwhile the garage confirmed with Nissens that the difference between the radiators was not significant.

Eventually, the time for a service came up, and with a full tank of petrol and instructions to test it on a motorway this time, the garage (a) reproduced the overheating and (b) continued to be mystified, as the thermostat and temperature sender and coolant had all been replaced, the cooling fans worked and the water pump was fine. The radiator was now exhibiting the bahaviour of being stone cold, even after an hours run on a motorway, even though the hoses to it were hot

- and I don't think radiators are *that* efficient. They got the problem reproducible in the garage simply by running the engine at over 3000 rpm for long enough. So they decided to replace the radiator (again) - this being the third replacement Nissens. Result - problem solved. No overheating. Even better, the replacement of the radiator was not charged to me.

So, the first Nissens radiator failed with a leak, the second failed with (I guess) an internal baffle failing - any bets on how long the third will last?

Cheers,

Sid