Radiator number 4

[Elannewbie]

Hi all

I haven't found any similar posts about the problem i have so here goes -

My original lotus rad let go soon after i purchased the car (approximately 3 years ago).

Replaced with a Boston rad aluminium replacement. After just under 2 years it started leaking from where the cooling fins are welded to the end caps.

Replaced with a Cool Experts aluminium rad and now after just over a year and a half the same problem is back but, not as severe (yet). The car does lose water but not a lot, no puddles on the drive and no droplets of water on the underside of the bumper.

I thought the coolant loss had been cured by fitting an alloy header tank as the original plastic header tank outlet boss/tube was cracked.

The only visible signs of leakage are very small droplets of coolant (the size of a grain of sugar) at the top of the radiator end cap where the cooling fins attach (drivers side only) when viewed through the bumper grill.

If anyone else has had a similar problem or anyone has any ideas I would be most appreciative.

Kind regards

Grahame.

[Fredjohn]

As it is a fairly new radiator I would suggest you speak to Cool Experts and maybe get them to give it a pressure test. It seems to me to be a very small hole/crack in the radiator itself at the top and therefore not a loose bottom hose. The top hose is on the passenger side, so your description does rather also eliminate that as an issue.

[Elannewbie]

I have contacted Cool Experts and they are just as miffed as I am. I am going to send the radiator back to them just as soon as rad number 4 is installed. Steve at C.E said they would pressure test it and possibly cut the end cap off to see if they can find the cause of the pin holes.

One avenue of thought (though I can't really believe it) is that electrolysis could be a contributing factor due to a bad earth and hence the radiator has become the sacrificial anode. I find this outlook hard to believe as if there was/is a bad earth I would be encountering other electrical problems.

I spoke to Tim at Lakeside Engineering and he thought the electrolysis scenario a bit far fetched and that they have had to replace aluminium radiators a number of times on customers cars as they had developed leaks.

I don't believe that the Cool Experts rad is a bad product as many members of this forum have them fitted with no issues.

I really need to get to the bottom of the problem as it's becoming a little tiresome changing rads every year and a half.

Kind regards

Grahame.

[Elannewbie]

Checked the radiator this evening, I now have seven little droplets instead of five since the last time I checked (just over a week ago), so it's getting worse.

Any thoughts from anyone much appreciated...

Grahame.

[Nickydee]

Might be worth doing a sniff test. Head Gasket failure on Elans normally results in abnormally high pressure in the coolant due to exhaust gases mixing with coolant rather than gunk in the system caused by oil and water mixing. Don,t want be a doom sayer and hope its not HGF but maybe more plausible than the electrolysis theory.

Cheers

Nick

[Elannewbie]

I did think it could be head gasket failure, and my line of thought could be wrong but, if there were abnormally high pressures in the coolant system the radiator inlet and outlet hoses would go rock hard! As both hoses stay "squidgy" at high coolant temps (fans on - and also coolant system pressure increases with temperature) I kind of ruled HGF out - could be wrong though...

P.S it was Max and Tim at Lakeside Engineering who advised me to check for "rock hard" hoses as an indication of head gasket failure.

Thanks for the reply.

Grahame.

[Elannewbie]

Sorry Nick, I should of mentioned that I use the car as a daily driver.

I would of thought that HGF would of manifested into Mayo in the oil and oil in the water by now. My rad problems have been going on for over 3 years now - and I do drive my car like I stole it...

Kind regards

Grahame.

[Elannewbie]

The guys at Lakeside also asked if I had trouble starting the car i.e HG failure "might" allow water to enter the cylinder when the engine is switched off and make it hard to start. The engine starts first turn of the key - every time, even when hot, but that's a completely different thread.

[Elannewbie]

Should of added - cars done just under 80,000 miles and head gasket was replaced at 69,000 miles - by previous owner.

[epipete]

Should of added - cars done just under 80,000 miles and head gasket was replaced at 69,000 miles - by previous owner.

There has been an awful lot of talk about HGF and it is true that original gaskets are getting old now. If the head was skimmed (you'll note that I'm making this up as I go along) could, even if skimmed within tolerance, there be a detrimental impact on coolant pressure (see I told you I was Blue Sky Thinking) that because the head is newly bolted down and elsewhere in the system is all new and therefore 'tight' is revealing itself in the Rad?

Maybe time I got up and fix something constructive with my day

Ps: I love your comment 'it's only metal, it cannot win'. It's one for the notebook for sure.

[Elannewbie]

I stand corrected, the head gasket went at approx 54,000 miles (thermostat stuck shut).

With that in mind surely in the last 24,000 odd miles all the parts should have "bedded in".

I did ask Lakeside if a sniffer test would be a wise test to carry out but, Max said that he used to do the test a lot but, the results were not very accurate so he felt it would not help.

Max did add that he had come across a vehicle with a cracked cylinder head which was causing over pressurisation of the coolant system but, as the coolant hoses on my car remain squidgy i can probably rule this out.

Also if the coolant system was/is over pressurising would it not cause a leak from the cockpit heater matrix before an aluminium radiator?

Kind regards

Grahame.

[muley]

Grahame

Just picked up on the fact it's your daily driver. I've an almost new rad with a tiny pinhole that could be fixed for a couple of quid that you are welcome to borrow - if that helps.

Rgds

Jim

[Elannewbie]

Cheers for the offer Jim, I have a new rad to fit but, my problem is - why do the radiators keep leaking after a year and a half or so...

The car is going into Lakeside on Monday so I hope i can get to the bottom off the problem.

Many thanks for the offer Jim, I really appreciate it.

Kind regards

Grahame.

[Enright]

I used to have a motorbike which always sheared aftermarket exhausts at the same place.
I never worked out if it was a combination of heat, resonance, the angle at which the exhaust naturally wanted to sit at...
But what I'm saying is perhaps you rad is being held in a position it's not "comfortable" with, and so it exacerbates fatigue.
Just a point worth considering...

[Elannewbie]

Dear Neil

I have had a look at the radiator mounting and there is a small amount of "float" so I'm happy that the radiator is not under any undue stress or load.

The new radiator was fitted a couple of weeks ago and all seems well at the moment, water level in the sight glass remains at half when checked (cold engine).

Kind regards

Grahame.

[Enright]

The new radiator was fitted a couple of weeks ago and all seems well at the moment, water level in the sight glass remains at half when checked (cold engine).

Glad it's ok, and long may it continue that way. If you need me to change the thread title to "5", just drop me a line (but I hope NOT to hear from you)!

[tb10]

This appears to be an odd one but not professing to know much about heads, but with the ongoing issues with your car, could there be an outside chance that somneone has put a N/A head on and applied the f**k it, it'll do approach to mechanics? I ask this as I know the N/A head is slightly different.......

Just my thoughts.

regards

John

[lotusles]

Hi, I note you live In Walton on Thames and use the car everyday, could it be external corrosion caused by road salt?

Also a good test to determine combustion chamber leakage is to do a cylinder leakage test.

Fingers crossed the problem does not re-appear.

[lotusflasherman]

Interesting thread and some of it very entertaining, laughed my socks off at some of the comments I hope this radiator lasts a long time but in case it doesn't a few comments that might be useful... or maybe not.

Some fundamentals seem to have been overlooked, or not understood at all. The coolant system is pressurised by being filled when cold and as it warms up the water expands causing pressure in the system. The pressure in the system is controlled by the design of the header tank pressure cap which, according to the Lotus Service Notes, is "110 kPa (15 psi)". Actually 110.3 kPa is 16psi and I have two Elans and a spare header tank and all 3 'black' caps are marked with '120' so reckon that's 120 kPa so probably closer to 17.5 psi. Water at 17.5 psi above atmospheric will get to around 123C before it boils and 15 psi above will boil at 121C so only a marginal difference anyway. (I have a feeling that yellow caps are a different pressure but hopefully somebody can confirm or correct me on this...)

The header tank on my 'daily use' Elan had gone opaque and had an antifreeze 'tide mark' so I couldn't see the actual water level so before swapping it with the more transparent spare I'd acquired I tested the spare. I bunged up the big outlet tube with a wine cork and put a tapered (airbed) inflator into a mains powered car tyre pump with gauge and pushed that into the smaller top tube to pressurise the header tank. Gauge was showing midway between 15 and 20 psi graduations when cap started hissing and gauge stayed at this position. I put the header tank into a bucket of water to check for any leaks from the seams - none. With the pump on a stream of bubbles came from under the pressure cap but none from the tank so tank was 'a good 'un'. I also tested the other pressure caps while I was at it and all operated around 17.5 psi. I should add that the mains powered pump has a considerable flow rate and the pressure caps had no problem 'dumping' all the excess air above their setting.

So, to the previous comments... Pete's Blue Sky Thinking about skimming the head having a detrimental impact on coolant pressure Too much vino Pete! Can't understand the logic behind that at all.

Max's suggestion that cracked heads or HGF over-pressurize the coolant system and radiator... well, a major failure between the combustion chamber and coolant system will pressurise the cooling system on the compression and power stroke but on the induction stroke the cooling system will 'blow back' / get sucked back into the cylinder and you are bound to get water into the oil and 'mayonnaise' on the dipstick, as well as steam out of the exhaust. If that cylinder is leaking into the coolant it will run badly too so engine will feel lumpy. A quick compression test of all 4 cylinders will tell you if anything is amiss in that department. The rate at which I saw air passing out of the pressure cap I doubt it will get much above 'the cap pressure' anyway, but may expel coolant as well as air so another obvious sign that things are not right.

The comment about 'the electrolysis scenario' I find interesting as an electrical power engineer... Cathodic Protection uses a sacrificial anode but the anode has the positive charge, the cathode is negative. Cars and motorcycles used to have the battery positive earthed until Ford realized that arrangement increased body corrosion and swapped to negative earth in the mid 60's, if I remember correctly. Other manufacturers then followed. Elan chassis is negative earth, so is the cathode, and anything connected to the positive would be the anode so there is a logic behind that suggestion. An engine without an earth strap might show a positive voltage with respect to the chassis.

It may be worth checking that you do in fact have an engine earth strap connecting engine to chassis and earth. If not, fit one quick. Without one the current from the starter motor can find some very strange return paths. Whether the radiator could be one is not something I've thought about but I had a friend in the mid-70's bought one of the first Vauxhall 'Shove its' (he called it a Chevette) off the Luton production line - basically an Opel Kadett with a new front end so it had a live rear axle with coil springs and panhard rod. My friend had 4 rear axles in the 12 month guarantee period. New axle would be quiet for a month or two and then start whining and develop a lot of backlash and there was a lot of swarf in the diff' oil. As he bought from a dealer in Stevenage the dealer got fed up fitting axles and took it back to Luton for the factory to check it over and they eventually found it had no engine earth strap. The big issue was current taken by the starter motor was going down the prop shaft, through the pinion and crownwheel, through the bearings into the axle case and via the coil springs to the body. Sparks across the teeth of the pinion and crownwheel was making tiny 'spot welds' that took the hardening off and pitted the teeth so the diffs weren't lasting. An engine earth strap cured the problem and the next axle was still on the car when he sold it.

If you do have an engine earth strap correctly fitted you can forget about 'electrolysis' and stray current theory.

[Elannewbie]

Hi Phil

The engine earth strap is present and correct and shows no signs of deterioration. At present the cooling system appears to be in good order and holding coolant. I am monitoring it closely and will post in due course if any more problems arise (fingers crossed hopefully none!)

Thanks to all who posted...

Kind regards and a happy new year

Grahame.