Overheating And Transmission

[Jonathan Stafford]

Hi

I am a new member with a 1994 GS 300, a lovely car. Under normal driving conditions it is ok but heavy driving such as up a long steep hill causes it to overheat, once at the top it cools down and is ok. I have had a new viscous fan fitted but still have the same problem. Also have problems getting 4th gear when in overdrive, if i take it out of o/d it will go back into 3rd, if i put it back into o/d 4th gear is sometimes gained, other times it goes into neutral. The problem seems worse under hard acceleration.

Has anybody got any ideas or solutions as i love the car and everything else seems to work.

Thanks Jonathan

[norkep]

Hi Jonathon,

Welcome to the club,

Overheating - sounds like you may have either a faulty rad cap causing pressure loss or a possible air block within the cooling system, you can remove the air block by taking off the rad cap (when cold) and start the engine, have a 2 Ltre bottle with coolant in and place over the rad, rev the engine slightly with the bottle over the top and sooner or later the air will release itself and the level in the bottle will drop. With the rad cap, may be a simple case of replacing the seals or the cap itself.

As for the transmission - bit more tricky, it could be a solniod inside the gearbox causing this, the friction pads within the box may also be causing this, best thing to do is to check the level, start the car, put the foot brake on hard so the car will not move even when in "D", foot on brake and move the selector from "P" to "1" and back again slowly, this will allow the oil pump to circlate the oil properly, then leave in "N", with the engine running, check the level of the gearbox oil, there will be 2 settings - Hot and Cold, both will have a Min and Max, you need cold and centre for this, even if you have been driving for a long period, it will take 70 + for an hour or so to get the gearbox hot enough to register on the "hot" marker. Also you can check to see if there is anything getting burning or getting burnt by the smell of the oil and the colour, light red is the colour of fresh and a sign of a good running gearbox, dark red to brown is a sign of a problem that needs addressing.

Hope this helps, sure some else will have more ideas as to a possible cause

Hope you get this sorts

BR

Paul

[Jonathan Stafford]

Hi Jonathon,

  Welcome to the club,

Overheating - sounds like you may have either a faulty rad cap causing pressure loss or a possible air block within the cooling system, you can remove the air block by taking off the rad cap (when cold) and start the engine, have a 2 Ltre bottle with coolant in and place over the rad, rev the engine slightly with the bottle over the top and sooner or later the air will release itself and the level in the bottle will drop. With the rad cap, may be a simple case of replacing the seals or the cap itself.

  As for the transmission - bit more tricky, it could be a solniod inside the gearbox causing this, the friction pads within the box may also be causing this, best thing to do is to check the level, start the car, put the foot brake on hard so the car will not move even when in "D", foot on brake and move the selector from "P" to "1" and back again slowly, this will allow the oil pump to circlate the oil properly, then leave in "N", with the engine running, check the level of the gearbox oil, there will be 2 settings - Hot and Cold, both will have a Min and Max, you need cold and centre for this, even if you have been driving for a long period, it will take 70 + for an hour or so to get the gearbox hot enough to register on the "hot" marker. Also you can check to see if there is anything getting burning or getting burnt by the smell of the oil and the colour, light red is the colour of fresh and a sign of a good running gearbox, dark red to brown is a sign of a problem that needs addressing.

Hope this helps, sure some else will have more ideas as to a possible cause

Hope you get this sorts

BR

Paul

←

[Jonathan Stafford]

Hi Paul

Thanks for your reply I shall try what you have suggested

Jonathan

[peter026]

Welcome to the club.I had the same problem with a Scorpio I once had,a new Viscose coupling fixed the overheating problem Had the auto box drained because the oil was brown,box cleaned, new fluid put in,problem solved

Let us know how you get on

[88b]

Jonathan, the two fault could possibly be related , there is a chance it's something like the ECT ( engine coolant temp sensor ) out of range and confusing the ECU. 4th gear is controlled electricaly on a lot of cars now. Does it still overheat if you go up the hill in 3rd ? and is it over heating or just the gauge going up ( again possibly a faulty sensor ). I would suggest you get a competent auto electrician to look at the car. Lots of supposed auto trans problems turn out to be engine management. You would not believe the problems a faulty mass air flow causes on an auto Mondeo, and the difference is £100 or £1500

[Jonathan Stafford]

Hi

The overheating seems to be the head gasket. Still having problems locating 4th gear solenoid, is it inside the gearbox and can you access it without taking the box out?

Thanks

Jonathan

[chips229]

Hi

The overheating seems to be the head gasket. Still having problems locating 4th gear solenoid, is it inside the gearbox and can you access it without taking the box out?

Thanks

Jonathan

←

Hi and Welcome to the Club.

Did you check the Autobox level was the colour of the fluid Red?

If you do have to change the Autobox oil only use the Toyota/Lexus dealer fluid as they use different additives in thee Auto fluid ive read and if mixed up with other Auto gearbox oil it sort of clots up.

Also on most Autoboxs theres a oil filter in them,maybe worth checking its not clogged and reducing the pressure it needs to work the torque convertor.

Like Paul says it could also be the clutches are worn.

Cheers chips.

[Jonathan Stafford]

Hi

Just to let you know that i've sorted the overheating and transmission. The head gasket cured the overheating and while the head was being removed two groups of earth wires from the gearbox were found connected to the inlet manifold and these were loose. On rebuilding these wires were connected properly and hey presto the gearbox works perfectly. Looking foreward to many miles of happy luxury motoring.

Thanks fot all your ideas and suggestions.

Jonathan

[chips229]

Hi

Just to let you know that i've sorted the overheating and transmission. The head gasket cured the overheating and while the head was being removed two groups of earth wires from the gearbox were found connected to the inlet manifold and these were loose. On rebuilding these wires were connected properly and hey presto the gearbox works perfectly. Looking foreward to many miles of happy luxury motoring.

Thanks fot all your ideas and suggestions.

Jonathan

←

Glad you got everything sorted out.

Happy motoring