Hi,
I'm new to this forum and hope you guys can help. (I'm in London, England)
We have a 1993 940 SE 2.0 litre Turbo (4 cyl) with an auto transmission.
One of the smaller water pipes burst after a long highway run.
Fixed this but have noticed an oil slick in the header/expansion tank. Its not like normal engine oil- its a light brown globby liquid. But it is oil as it floats to the surface and stays there.

Did the tests:
No evidence of water in the oil dip stick
Hold my hand over the header tank filler when engine running= no pressure.
No steam out of the exhaust
No overheating

Car runs beautifully.

Any ideas?
Pete

Thanks Spook,
Will check the ATF before driving it again. Have driven it about 20 miles-hope it didn't screw up the transmission....
Pete

Dear Pete,

Good p.m. and may this find you well. Unless there's a huge amount of water in the ATF, 20 miles of driving will not do huge damage. The Aisin-Warner trannies are very durable.

If, by ill fortune, the tranny has been ruined, do not get it re-built: that is a huge waste of money (it will surely cost ₤800-1,000). Rather, find a salvage yard, and get a replacement tranny. Key point: the donor tranny should have clear, red ATF. If at all possible, pick the donor car and inspect the fluid yourself.

Please post back with your findings.

Yours faithfully,

spook

Dear Pete,

Good p.m. and may this find you well. The symptoms do not suggest that the headgasket has been compromised. Apparently you shut-down the engine quickly.

However, you might take a look at your transmission dipstick. The fluid (automatic transmission fluid [ATF]) should be a clear, rosy red.

If the ATF is milky (i.e., not clear), then water has gotten into the ATF. The reason: the ATF cooler - part of the radiator, on the driver's side (UK models) - has failed.

While a bit of ATF in the coolant does no harm, coolant in the ATF will destroy the transmission. The water will dissolve the glue that adheres the clutch pack facings. Free-floating clutch pack facing fibres will clog the finely-machined fluidways inside the transmission.

The cure: flush the transmission AT ONCE! Use a good quality ATF. The AW71 transmission holds 9 US quarts (about 7.5 UK quarts). Drive for 500-1000 miles, and the re-flush with Mobil 1 Synthetic ATF.

If the ATF is clear, but discoloured (brown, black, etc.), the fluid is old and should be replaced.

As to the oil in the coolant, if it is a thin film, it may simply be cooling system gunk that formed when the engine over-heated. You can flush the cooling system to purge it. I had this problem with a '93 940: blackish, oily scum. A thorough flush and refill with fresh coolant made the problem go away.

Hope this helps.

Yours faithfully,

spook

Dear Spook

Hello this is Richie (baracuddda@aol.com) crazypierre's brother yes i have milky fluid in my auto box dipstick. I own the 1991 not 1993 Volvo 940 Turbo Auto. What should i do next. Do i need to change the radiator or just the atf fluid.? Can i try one of these propriotory branks of coolant sealers ?

Richie

You can try to pinpoint this by adding fluorescent dye (from Halfords) into the motor oil and then looking for the glow in the coolant reservoir with a UV lamp (also from Halfords). If no glow, then the AT cooler in the radiator is leaking and you need a new radiator.

I suspect head gasket, though.
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See the 700/900 FAQ under 'Select Link' button on the top right.

I had this problem on my daughter's "92 960. we cut the lines to the transmission part of the radiator and added an auxiliary transmission cooler. We then attached the cooler lines. We pulled the coolant expansion tank, drained it and cleaned it. She's driven the car around 2-3,000 miles since this cheap repair. the expansion tank has remained clear.

Michael '95 960, "98 C70, "98 XC 70

Hi
I wanted to let you all know that the problem was solved by repacing the radiator with a new one. We also changed the trasmission fluid and all seems fine now. Must have been the transmission fluid cooler in the rad that has a hole in it. Thanks to everyone for their help.
Pete