Lotus Elan and Lotus Elan Plus 2 Forums

Hi there

My S4 has chosen to run hot, if the outside temperatur is above 23 Celsius and the car is stationary for a moment, or in traffic, water temperature soars to 100 Clesius and more. The fan does kick in, but the temperate falls down very slowly and only when the car is driven at high speeds for some time.
What could be the cause? Radiator? Or waterpump?

Thank you very much

Great to have an Elan-Forum at last.

Swap out the standard fan for a Kenlow or similar. Flush through the block and rad with a flushing agent. Test it and if it still runs hot could be the water pump

The S4 has a Triumph rad which is really a bit small for the Lotus engine. You can get 3 row versions of this rad or to really solve the problem get a racing rad from Tony Thompson. This is the route I think I will be taking with my S4.

My +2 was running hot during the last bout of hot weather. I changed the coolant and used a high quality antifreeze. The car runs a lot cooler now. I was suprised by the difference. :unsure:

Jolly Jumper,
As someone said flush out the radiator or better still have the rad cleaned out by the radiator people, radiators accumlate sediment and block the tubes. You say it gets hot standing in traffic, fit a new thermostat (for the price its not worth even testing it) add new anti-freeze/rust inhibitor.......VW G11 highly recommended
and make sure your electric fan is working .........check switch.
The problem is unlikely to be the water pump UNLESS it is leaking and you have water loss, the internals of the pump do not normaly give problems unless the bearing/seal is defective but this causes water loss......back to square one!
We could start talking head gaskets but that a bit premature at the moment so I hope this helps.
Regards Brian.
64Elan/72Sprint/J.P.S.Europa

Thanks for the replies, keep'em coming.
The water pump is not leaking, so I do not think it's the fault (at least I hope so)

How do find out if I have a 2-row or 3-row rad? Can you tell from the outside?
And is the Kenlowe Fan a straight swap for the original one? :unsure:

The best to check how many rows your rad has is to remove the rad cap and look inside (you might need to let a bit of water out) You should see the top of the matrix and just count the rows

The Kenlow or similar is a bigger and more efficient fan (better blade design) As the car already has an otter switch to turn the fan on/off all you need is the fan. Take off the old fan and brackets, bolt on the new fan, wire up and away you go.

BTW: no one has mentioned air locks The S$ cooling system can be a right pain to fill and not get an air lock. When filling the system make sure the heater is on and jack up the front of the car as high as you can.

I have just restored a stromberg headed S4 and have experienced almost the same problem. My temp was running past 96 when stopped. At speeds above 50 the engien will run at stat' setting (82C). I have a 3 row rad and have invested in a new Pacet Fan. I have moved the recuperator bottle from the air stream (to gain air on rad) and have fitted an alloy version of the pressed paper deflector at the bottom of the rad. I still have the same problem! The fan fights to contain to 90C when at rest. I have just concluded that the 3 core rad (that I have) has a great opposition to air flow. When the hand is place at the rear of the rad, the air through the matrix is very poor. I beIieve the element gaps between the core tubes are too small and the extra row limits air through the matrix. I am going to find an old two core rad (origial spec' pitch) and try it.

Update!

Just found a cheaper alternative to the Tony Thompson racing rad. It is a similar system using a modern core and swirl pot but less than half price. It uses a modified Elise rad and custom made swirl pot. I should be getting mine in about 4 weeks. However by the time I have it fitted I think winter will be well and truely here so we will have to wait until the spring to see if it works.

Is the fan belt tight? I was having overheating issues with my Elan. Had the radiator re-cored to more rows, replaced the 10" electric fan with a 12". All to no avail. I then had the really bright idea that maybe the belt was too loose. Tightened it up some. Like magic no overheating! Of course that simply remedy WAS about $200 later... ouch. But for Florida you can't really have too much cooling capacity.

Mike G

I had the same problem on my +2.
It turned out that the radiator was blocked, you can check for this by feeling for cool spots on the face (watch your fingers though).
I had the radiator re-cored at half the cost of replacing it.
I don't know whether all elans are the same, but on +2's there should be a deflector plate over the front crossmember to push as much air as possible through the radiator.

Steve
69 +2

Hi, Re S4 running hot.

Latest update on mine. I managed to obtain an old original (but ratty) rad from a friend. I have compared the matrix with the one that I am having fun with. Incidently, I had this recored up to the three rows. The car is not yet run in from the restoration rebuild. Hence the troublesome rad is very new.

Findings: The vertical core tubes on the old rad are spaced further apart. Also the pitch of the cooling fins is dramaticacl different. Basically you can hold the old rad up and see the wife through it. With the new 3 row (dense one) you can see nothing. Hence air flow through is much less. As a layman I would say at least 50%.

I have been in touch with a boffin at the rad' place and he agree that my own problems are not being helped with the core density and the inabilty to allow air to flow through it. They are having the rad back to put it back to original core tube and fin pitch spec'. It is questionable whether they go to three rows. They are going to look into it. Hence re-cores are not always the answer if the rad character is altered dramaticaly by incorrrect matrix spec'. Hope this helps.

Mike

Check the fan blowing not sucking, seen this before especailly if you disconect the fan and swap the wires by accident! :rolleyes:

Dave

s4

Jolly Jumper,
All good replies. I think if you have all the basics covered, you should be in good shape. Sounds like the waterpump is OK, which is very good. Certainly consider an rad upgrade. Well worth it.

Greg Z.
'72 Sprint