Lotus Elan and Lotus Elan Plus 2 Forums

Like many others my S4 been plagued with overheating. Nothing I've tried over the last 30 yrs has solved it but I've recently managed to improve matters a little. I've got the std narrow rad but some years ago had it recored to a three row matrix. That made quite a bit of difference initially but over time it seems to have slipped back to its bad old ways. I recently (two yrs ago!) cleaned it out with rad cleaning chemicals and that improved things substantially.

Stuff I've found that helps - upgrading the rad as above, making sure the system is full by filling it with the nose of the car in the air, making sure the (std) electric fan comes on early (I use a manual override switch), wrapping the manifolds in heat resisting tape, and pulling the bonnet catch to let it rise up a couple of inches at the rear. Only really of much help if you're stationary in traffic but it does stop the needle rising more or less completely.

Stuff that hasn't helped - cutting holes in the wing, adding stuff to the coolant (like water wetter), renewing water pump, hoses etc, renewing water temp gauge.

Again like many others I've sat in traffic watching the needle rise to higher and higher numbers, getting more and more fractious and waiting for what I thought would be the inevitable cloud of steam. To date though it's never happened. I've had the engine start to misfire with fouled plugs and I've had the clutch hydraulics fail when the manifold heat boiled the fluid but I've never boiled the engine over despite seeing the temp needle seem to come so far round as to almost start again. Something must be going on that I'm not aware of. No 1 suspect at the moment is the reading on the temp gauge. I have wondered whether what I'm seeing is just a localised reading from the sensor located as it is just over the top of the manifolds and that the heat is soon dispersed when it makes it into the rest of the system.

I guess I'm really lucky. My temperature on the road is always about 85?C which is handy as the Smiths dual guage needles point to 12 and 6 o'clock at decent road speed. When I get into (stop and go) traffic I just reach down and switch on the electric fan and the needle stays below 90?C.

Galwaylotus wrote:I guess I'm really lucky. My temperature on the road is always about 85?C which is handy as the Smiths dual guage needles point to 12 and 6 o'clock at decent road speed. When I get into (stop and go) traffic I just reach down and switch on the electric fan and the needle stays below 90?C.

Being S3 I assume that's with a wide rad'?

Don't know. How do I tell the difference?

http://www.elanfactory.com.au/pdf/techn ... 20test.pdf

I had 7 years of hot running and this test helped me determine that my water had been installed incorrectly. I would recommend trying it. Dan

Galwaylotus wrote:Don't know. How do I tell the difference?

The wider radiators take up all of the space between the front bonnet channels with the header tank/matrix. The later, smaller rads have metal plates at the side to fill out the gap because the matrix is narrower. It's obvious when you see one, if no-one beats me to it then I'll take a picture and post later on today.
Brian

There is NOTHING generally wrong the standard Elan cooling system! It worked on many racing ?lans in the 60's without problem.

However, in my own experience, owning and maintaining ?lans for 40-years, one generally overlooked issue should be resolved first i.e. make sure the cooling system is able to maintain coolant to full capacity.

The standard radiator filler cap is designed to both expel excess coolant under pressure to the expansion bottle (as the system gets hot) and retrieve coolant from the expansion bottle under vacuum (as the system cools down). It is the mechanics of this retrieval that?s the problem.

Let's consider that the cooling system (including expansion bottle) has been filled in the normal manner i.e., all 4-wheels on the ground and the radiator filler neck BELOW the thermostat outlet. Now, as the engine goes through its first heat cycle, the air retained within the cooling system is expelled via the radiator filler cap/neck and expansion pipe and into the expansion bottle from where it will go to atmosphere. As the cooling system cools, a vacuum is created within the engine cooling system and, providing the expansion pipe is below the water level in the expansion tank (and that the expansion pipe to radiator is air tight) then the vacuum valve in the standard radiator filler cap will allow coolant, and ONLY coolant, to be drawn back from the expansion bottle and into the cooling system; thus filling the cooling system with coolant.

The MAJOR problem experienced by owners today is that the filler cap rarely seals on the metal-face of the standard radiator filler neck. The metal-face of the filler neck is usually distorted and/or damaged (nicked). Therefore, a vacuum cannot be created and the coolant volume not restored. In short, coolant is lost from the system during heat cycles only to be replaced with air.

ANSWER: fit a thin rubber/neoprene seal to the standard pressure relief filler cap.

The flat (non-pressure relief) radiator filler neck sealing caps that are available DO have a thin rubber/neoprene seal. Get a flat cap, remove the rubber/neoprene seal and fit that to your standard pressure relief filler cap, fill the radiator with coolant, and fit the now 'sealed' radiator pressure relief filler cap.

Providing the rest of the system is in good order; I'll be amazed if that doesn?t cure your problem (on this and any other car you have with a metal-face filler neck).

PLEASE try this simple resolution BEFORE spending lots of money on modified radiators, water pumps, coolant additives, etc., none of which will solve the basic problem.

The standard cooling system works (every time I remove my radiator filler cap the radiator is FULL of coolant). It worked on racing ?lans in the 60's. It has worked on my Elan for the past 35-years and 250,000 miles (including the in-roads, coastal roads, and Alpine regions of summer France and Italy) without problem.

So to the picture: #1 is of a flat cap with seal; #2 is of the seal removed, #3 is of the standard radiator filler cap, and #3 is of my current filler cap with seal fitted.

Hope this helps?

UAB807F wrote:

Galwaylotus wrote:Don't know. How do I tell the difference?

The wider radiators take up all of the space between the front bonnet channels with the header tank/matrix. The later, smaller rads have metal plates at the side to fill out the gap because the matrix is narrower. It's obvious when you see one, if no-one beats me to it then I'll take a picture and post later on today.
Brian

Here's my radiator:

Hi all,

Having read a few of the posts, I'd just like to add that Clive Baker,or cliveyboy on the forum has a good solution to the problem. He makes and sells a new and improved filler position, it's the elbow above the thermostat with a filler point, this ensures that at least you fill up from the highest point.

Another item is a full width radiator with one or two electric fans, your choice.

Both of these will help keep any lotus cool.

Just to confirm, nothing to do with me apart from being a very happy customer.I have some pics of these on a post from a few months ago if you want to look at them.

Paul

Galwaylotus wrote:Don't know. How do I tell the difference?

Yes as Brian says the wide rad' doesnt have the wide metal brackets on either side just a nice big wide radiator.

It has always been my understanding that Lotus went over to the narrow rad' with "ears" when Triumph from whom they bought radiators changed the fitment to Spitfires etc. Knowing Lotus it was done for cost reasons alone and certainly not because a smaller rad' was better for cooling the cars.

IMO having owned an original Sprint just as it came out of Lotus back in the 70's cooling on later Elans with the narrow rads was always marginal. It doubtless helps if you can fill the cooling system as full as possible but the best solution will always be a radiator which has plenty of capacity and a large surface area for air flow.

that looks a bit like mine.....



which is one of the full width ones. The sprints are noticeably smaller, about 2/3 the width.

Brian

UAB807F wrote:that looks a bit like mine.....

which is one of the full width ones. The sprints are noticeably smaller, about 2/3 the width.

Brian

That's a proper radiator


PS
When Triumph went over to the narrow rad' (which I assume was marginally cheaper to produce) the models fitted with them were also a nightmare on sunny days in traffic.
My old Spit' used to get very hot under the collar.

Sage advice, indeed.

nebogipfel wrote:
That's a proper radiator


PS
When Triumph went over to the narrow rad' (which I assume was marginally cheaper to produce) the models fitted with them were also a nightmare on sunny days in traffic.
My old Spit' used to get very hot under the collar.

Hi, What would be the opinion of you guys as to the cooling effect of a narrow radiator altered to a 3 row core as opposed to a standard wide full width radiator, ie. is the full width still a better bet?
Regards, John

On S4 cars it helps to recore the radiator with a three row, add blanking panels on either side if the originals are missing and it"s important to use a thermostat that's the correct temp, 82c. A thermostat that's too cool will actually cause the system to overheat.