Lotus Elan

Engine Cooling

PostPost by: theelanman » Wed Jan 12, 2005 4:10 pm

strange thing........the water pump was replaced about 100miles ago......the gaskets are all new.......the oil pressure is fine........the oil it good quality and still in excellent condition....I cannot see and leaks anywhere.....however the car seems to be 'drinking' water by the litre.........in the 100miles I have done I have replaced 4 litres of water.........I cannot see anywhere where the water is going....nothing in the engine bay is 'wet'... the pump is fine...the gaskets are fine....the oil is still oil and not that white gloopy stuff...(not emulsified)......
where can my water be going.....yes Ive checked the rad....no leaks there either.....I cant figure it out....anyone got any ideas???
thanks
G
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PostPost by: type26owner » Wed Jan 12, 2005 4:26 pm

Out the exhaust. Place a metal container filled with cold water in the exiting exhaust stream and observe the amount of condensation forming. Now go do the same thing to an engine that does not leak. If they differ by quantity much then you've found your water leak. Suggest you go buy a chemical test kit for detecting CO in the radiator water ASAP. Well worth the cost! While you're at it might as well buy the Ph paper test strips and the hydrometer for checking the strength of the anti-freeze. Having the correct tools helps out a bunch!
Good luck,
-Keith
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PostPost by: charles jackson » Wed Jan 12, 2005 4:49 pm

From the amount of water per 100 miles it would be difficult to expect it to be gasket failure. The system would be pressurised to such an extent it would be pumped out of the overflow pipe. Check your core plugs especially the one at the rear of the cylinder block which could leak via the bell housing. Another item to consider is the heater matrix which would leak into the cabin.

Keep us all posted - regards Charles
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PostPost by: type26owner » Wed Jan 12, 2005 6:09 pm

Suggest you pull each spark plug and if one has the insulator absolutely clean then you've found the leaking cylinder(s). Also peer down at the top of the piston if there is water leaking there then it will be carbon free too. Don't run the engine for long while this problem exists because the oil is wiped off the cylinder walls and the piston rings will destroy the bore quickly. Retorque the head first before panicking. Hopefully you read my suggestions posted on this forum on how to get the headgasket to seal up so the MTBF (mean time between failures) is maximized. Tricky, risky stuff at best. The big CTE (coefficient of thermal expansion) between the cast iron block and the aluminum head works against you on the twincam by applying a huge force in shear across the headgasket. The modern day fiber technology headgaskets are the way to go according to the application engineers I've chatted with. That's what most all the racers are using.

Oh! If the water leak is big enough that the cylinder fills up with water while the engine is shut off there is a real risk of bending/breaking the crankshaft, conrod or bursting the cylinder wall in the block when cranking it over while trying to start it. If you suspect a leak I suggest just bumping the ignition key many times with the coil disconnected to make sure there is not a hydraulic lock situation first before starting the engine. Danger Will Robinson! :ph34r:
-Keith
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PostPost by: theelanman » Thu Jan 13, 2005 10:14 am

keith
if the water was in the cylinders and wiping the lining of oil wouldnt that lead to emulsified oil in the sump????...I thought the white goo was a dead give away.....I'll have a look anyway as the car has been to bed for the past couple of weeks due to the weather.....and I was going to tune it in the next couple of weeks with the old faithful colortune
cheers
Gareth
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PostPost by: twincamman » Thu Jan 13, 2005 12:17 pm

had much the same problem in my 7 and the sprite added an overflow bottle for the rad ----its all good --- no loss of coolant at all ed
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Editor: On June 12, 2020, Edward Law, AKA TwinCamMan, passed away; his obituary can be read at https://www.friscolanti.com/obituary/edward-law. He will be missed.
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PostPost by: type26owner » Thu Jan 13, 2005 3:01 pm

Hi Gareth,
Unfortunately diagnosing the source of a water leak can be an extremely difficult task. Assuming that all is well because no emulsion is to be found in the oilpan is not all that reliable. I've given you two easy ways to check which can be completed in about 30 minutes of effort. Usually those methods are fool-proof for the leak rate you've described. Smaller leaks can be an exasperating process to find and give mechanics nightmares.

If there is not a coolant overflow recovery tank installed along with the correct radiator cap then the fluid level will go down naturally creating an aircap. The radiator cap must be a dual seal type to actually function correctly and recover the expelled coolant. The vacuum break valve many times has an anode built-in as a component which is usually the rivet or the spring. Due to errosion of the anode the valve can fail to seal and it will not be readily apparent unless you look for this problem. I finally purchased a radiator pressure checking tool kit because I was having issues with the Elan cooling system too. One of the interesting things I found was about 1/3 of the radiator caps pressure tested to be defective by not holding the rated pressure when they were brand new right out of the box. Best practice is not to ASSUME anything.
-Keith
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PostPost by: flyinggellyfish » Thu Jan 13, 2005 8:46 pm

Have you checked the rad cap is not faulty ie the seal is worn or torn .

Rick
1968 Elan +2 . Now going back together after 18 years , you just can not rush these things .<br>Rick
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PostPost by: charles jackson » Fri Jan 14, 2005 12:39 pm

Folks! we are talking about circa a gallon of water per 100 miles, thats a heck of a leak and if its in the cylinders than surely there would be a major misfire if not a major hydraulic issue.

I am interested to learn of the outcome - Charles
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PostPost by: type26owner » Fri Jan 14, 2005 2:04 pm

Hi Charles,
It will merrily go about flashing the water into steam inside the combustion chamber. Takes a lot more water than that to cause a misfire. There's lots of info about water injection systems on the web if you're interested. Water injection is WWII technology. However, piston slap comes to visit though shortly if the oil film on the cylinder wall is diluted enough to cause the rings to make too much metal to metal contact. Attention to minute details is essential when replacing a headgasket. A single scratch in the metal can be fatal.

Kinda surprised no one here has mentioned trying a nitrous oxide and water injection system on the twincam before. It's a stout engine and could take doubling the horsepower for a few seconds at a time. I'll bet it will not blow up on the first pass. Plenty of rice-rocket mechanics have the expertise to do the installation now.
-Keith
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PostPost by: charles jackson » Fri Jan 14, 2005 2:43 pm

Hi Keith,

sure I take on board your comments re increase in power towards water injection albeit with this issue surely there will be immense pressure build-up somewhere. Lets hope the owner is able to trace and identify the problem and posts for all to see.

Regards - Charles
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PostPost by: type26owner » Fri Jan 14, 2005 3:32 pm

Charles,
Unfortunately the benefits of water injection are minimal for the stock configured twincam running on petrol. Racing engines really benefit from the detonation suppression effect. Nitrous oxide systems need it because the increase of combustion heat can cause the coolant to flash over overwhelming the cooling system. The latent heat of the water absorbs the extra heatload and it exits out the exhaust. Pretty much a given if the power output doubles then so does the combustion pressure. Good way to potentially position yourself in the minimum time before a failure end of the bell curve.

Went back after thinking about this and hedged my bet comment above. :rolleyes:
-Keith
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