engine cooling

[Jean]

Hi!
I am the lucky owner of an Interceptor II LHD. Since the fans were swapped (brand Bosch bought from Rejen) the temperature of the engine coolant gets high when driving in town or in low speed. I 've had the radiator changed (aluminium model) as well as the temperature sensors. I have also put an electronic ignition and changed the exhaust collectors. The water pump works. The fan blades seem to be weak.
Are there any fans or blades that would suit and prove more efficient?

Thank you for your help.

Jean.

[Martin R]

Hello Jean,

Firstly, the temperature gauge on an Iterceptor can over-read.

Secondly, if you're using a standard alternator, the voltage supply at tickover in traffic can be well below what a modern unit can deliver, so you might have a situation where the fans receive less than 12v in slow traffic.

Normally, with the Bosch fans and a new radiator, the cooling should be OK.

Are you sure that both fans are correctly wired so that they both rotate in the same, correct direction? If one or both are "sucking" rather than "blowing", it will overheat.

However, even if everything above is OK, if the engine waterways are blocked or partially blocked, cooling will be an issue.

[slotcarone]

Jean you said since the fans were changed. Did you not have this problem with the old fans? One thing that I have found very critical with these cars is the coolant level. You should have the overflow tank no more than half full cold. When cold take the cap off of the radiator and add coolant slowly until it will not take anymore. You may not be able to add much but I have found this makes a difference. Keep adding slowly and it will go down slightly and add more until it stays right at the neck bottom.

[Richie]

Good advice here... after checking the radiator is indeed full, as Martin suggested, make sure the fans are turning in the correct direction... but they should be sucking through the radiator.

[Chris_R]

Jean,
From your comment it seems that it was all OK before the changes?
If this is true, the logical conclusion is the new components are not compatible with your car. When you change so many items and it then does not work propoerly it is almost impossible to determine which one is the problem.
I would suggest you refit the old radiator, the old fans and the old temperature sensors. Then if you wish, perhaps change one item at a time and see what happens.

[RayR]

Jean,

Agree with Chris, review the changes. When you changed the radiator did you keep all the radiator shrouds? Fan shrouds & cooling flaps? etc. Personally I would switch the sensors back first to make sure the problem is real. Interesting that the fans seem 'weak' though.

Ray

[Steve Payne]

You need to check which Bosch fans you have, most of these fans look the same but the actual power output is very different. Also some are Chinese copies and these can be even lower.

The fans I normally fit are the 250watt versions so if you check the amp these are drawing while they are running they should be close to 20amps each. If as I suspect they are the smaller 100 or 150 they will only be drawing 8 or 12 amps. You need to use the two outer terminals as this is the higher speed.

As Martin has correctly said bigger fans need more electricity, the standard Alternator struggles to supply enough for the original fans at idle so an Alternator upgrade is a sensible upgrade.

It is also worth changing the thermostat for a high flow version, this can make a big difference.

Steve

[Jean]

Thank you all for your valuable help and advice.
Steve, when you say "You need to use the two outer terminals as this is the higher speed."
What do you mean?
THX
Jean

[Steve Payne]

Steve, when you say "You need to use the two outer terminals as this is the higher speed."
What do you mean?
THX
Jean

The fans that you should be using because they have the higher output are 2 speed fans, the earth and the inner terminal is low speed and the earth and outer terminal is the high speed. If you only have 2 terminals send them back and order some decent fans as the ones you have are 100 Watt.

As I said earlier you need the 250 Watt versions of these fans.

Steve

[RayR]

Hi Steve, it might be helpful if you have the Bosch part numbers for these fans.

I run the Bosch 0130107077 which they list as 200 Watt. They have performed flawlessly for over 20 years and well over 100,000 miles - including many years in Phoenix Arizona, which is a very challenging environment!

I would be interested in the 2 speed version now I am in NZ, control it to start on low and if does not turn off after a set time go to high.

Ray

[Steve Payne]

No problem

The Bosch number is 31 65142 83185 5 and the Hella number is 40 82300 14363 8

Be careful were you source them from as there is a lot of rubbish out there, some when measured are only about half there advertised power output.

Don't just think you can put a pare of these on with the standard wiring, upgraded wiring and relays and an Alternator upgrade to get the best out of them.

Steve

[RayR]

Thanks Steve,

Yeah, following recommendations when I installed them, I upgraded the wiring and added a relay for each fan and installed the K&D Delco alternator upgrade. Other than a noisy alternator bearing all has been good.

Ray

[Frankoid]

Has anyone tried waterless coolant? It does not expand with heat and so does not stress out the ancillaries. When I got my car it was overheating. I got a new thermostat, new (old) Kendal fans, and relays. It was still overheating so I checked the gauge. A previous owner had connected the voltage stabilizer to the oil pressure gauge rather than the temp so the oil was under reading and the temp was overreading Now I have 40 psi oil and normal temperture after a long runs during our recent hot weather

[Steve Payne]

Waterless coolant is a sticky plaster. If you're car is overheating you need to find the reason.

Good quality components with a good state of tune is the answer to most cars. Cheap thermostat and a rubbish water pump with a partially clogged head gasket and you have a problem.

Steve

[Chris_R]

Absolutely agree with Steve. Waterless Coolant doesn't make your engine run any cooler, if anything it will run hotter than before. Waterless Coolant simply doesn't boil when it gets to the same temperature that water would boil at so the only problem you solve is the boiling. Waterless Coolant has approximately 65% of the heat capacity of water. By contrast a 50% mix solution of water/ethylene glycol antifreeze has between 80% (at 0c) and 85% (at 90c) of the heat capacity of water. In laymans terms what this simply means is that Waterless Coolant cannot take away as much heat as water or even of water/antifreeze. Result? Unless you can pump more coolant through the system to take the heat away then more heat stays in the engine = an even hotter engine with hotter under bonnet temperatures. But it won't boil though!
But to be fair, having said all that, one of our members who came to Turin on the 50th anniversary trip has Evans Waterless Coolant in his Interceptor III and had no problems whatsoever so quite possibly if you have a good cooling system already then it will work.