Coolant leak

[ashm]

Ok, another problem raises its head! It's like whack-a-mole sometimes with this car...

The Elan has been slowly losing coolant since I got it in April. I've had a good poke around under the bonnet, there's evidence of a prior leak (orange crusty stains) around the offside end of the main radiator, but I haven't actually seen any coolant leaking from that area. The only clue is a hissing noise from behind the expansion tank after a run, but I can't see or feel any steam or coolant escaping from anywhere. I've reseated the hoses and replaced some of the hose clips, but that doesn't seem to have sorted it. Regardless, the temp gauge was solid at 1/4 when driving, rising to 3/4 when stationary and dropping again when the fans come on so I wasn't particularly worried.

Now the hissing/bubbling noise is more dramatic, but I still can't see where it's coming from. The coolant level keeps dropping to the bottom of the tank and this morning the temp gauge sat at 1/8 for the whole journey.

Any suggestions? My first thought is a leak from the underneath of the expansion tank.

Adam

[texas2201]

there have been a number of cases of the expansion tank splitting - see some of LGM threads - I believe she has made an aluminium one as a replacement

the other thing (and it happened to me) is this could be a sign of HGF!!! is the water "dirty"?

[John_W]

ashm,
No tell-tale drips anywhere on the ground I suppose?

My car had held water level rock-solid all the time I've had it until at the start of the year I noticed the coolant header tank being low. Funny I thought, and topped up. I kept an eye on it and it needed weekly top-ups, so I had a look around and found wet bits on the bottom of the radiator. It turned out that the head of the bleed screw under the LHS headlight pod had sheared off, allowing a fine drip to escape.

It's worth a look under the headlight pod to check. See here for pictures.

John

[texas2201]

viewtopic.php?f=80&t=10210&p=164199&hilit=+expansion+tank#p164199

[ashm]

Hmm... given the many failures of stock expansion tanks, is something like this a good idea?
Has anybody fitted one of these? Is it worth the extra cost?

My main concern would be that it's surely a lot harder to check the coolant level. I'd almost be tempted to make up one of my own, although it'd be brazed as welding ally is a skill I lack!

Ad

[bobbrown]

Another source is the main water pump
It happened on mine and did not leak with the engine running and there was no sign of a leak till I took the expansion tank cap off then drip drip drip.
The coolant system was going into a partial vacuum so the leak stopped when cold.
May be some paper under the car and remove the expansion tank cap when cold, and it should help identify the exact area the leak is coming from.

Bob

[RichardK]

Ditto - John - I had the same problem with mine two weeks ago, the bleed screw head had cracked and was "wet". It sheared completely as I tried to remove it. Given my car has been pampered all it's life ('92 SE, 25k and until I had it always been in a heated garage with monthly runs), there must be alot of cars out there with this just about to happen. Still, it gave me the excuse to refurb my pods, replace the coils....... damn project creep ..

[bobbrown]

Hmm... given the many failures of stock expansion tanks, is something like this a good idea?
Has anybody fitted one of these? Is it worth the extra cost?

My main concern would be that it's surely a lot harder to check the coolant level. I'd almost be tempted to make up one of my own, although it'd be brazed as welding ally is a skill I lack!

Ad

Have a word with Roy at Ralloy he has made up custom tanks for me in the past along with a lots of other custom parts and I'm sure he could make one with a sight tube down the side.

Bob

[ashm]

Hmm... well I'll check the bleed screw and probably get a cheap Nova tank anyway as the current one is pretty filthy. I'm due a cambelt change so the water pump'll be changed soon anyway. The rad or HG are the only possibilities that'd lead to major expense I wasn't already planning, I suppose.

I'd like an alloy tank with a sight tube, but that'd have to wait for a few more paydays to go past! I'll keep it in mind - thanks Bob!

[dapinky]

Whilst all of the above are very valid posts - I'd start off with a 'cheap and chearful' check/repair........


....The rubber washer/seal inside the radiator (expansion tank, actually) cap will deteriorate with age and if the top face of the bottle is nicked in any way there won't be a 100% seal under pressure.

This would give all the symptoms to describe, and account for loss of coolant/lack of drips as any escape would be by way of vapour or boiling water which would soon turn to vapour.

An easy (temporary) check/repair is to turn the washer over so a 'new' face is doing the sealing, or give it a smear of silicone sealant.

If this shows improvement, splash out 50p or so on a new washer, a few quid on a new cap, or whatever a new expansion tank will set you back (depending on where the defect is located).

[tigerdog]

is something like this a good idea?

I started a thread on the subject but it mostly died a slow death due to lack of interest. The expansion tank only seems to be a priority when its broken, I guess. Anyway, Canton Racing expressed interest in creating a tank but require a 10 unit minimum.

[Monty]

Get a Block tester of ebay about £30 just to rule out HGF ie combustion fumes getting in to the cooling system

[muley]

If it IS the rad - and it sounds suspect - it doesn't cost that much to have them recored

Jim

[Dave Eds]

Get a Block tester of ebay about £30 just to rule out HGF ie combustion fumes getting in to the cooling system

agree with Murph - had rad and hoses go over fair period of time due to progressive HGF.

[ashm]

Well, it seems now my thermostat has gone as well. Yesterday evening the temp gauge was nailed to zero until I stopped the car and ran it stationary while poking around in the engine bay. After a few minutes the gauge rose to maybe 1/8...
So, shopping list:
Thermostat
Water pump
Header Tank

...hoses?

The radiator bleed screw looks fine, incidentally. I'm not too worried about the head gasket as there's no gunk in the oil, no oil in the coolant, oil pressures are fine and no obvious signs of the contamination I'd expect if combustion gases were getting into the coolant. But of course a compression test is a good idea to make sure.

[Dave Eds]

Don't be fooled - do the test, it's the right place to start! I had no visible signs in water or oil of HGF, but the HG was the last thing I did after numerous stats, hoses, rad, water pump et al. Establish what you have or haven't got for £30 - no brainer Get some Samcos while your at it if it is HGF.

[ashm]

Just to add to the saga:
Yesterday I wondered if maybe there was some air somewhere in the rad, expanding when hot and partially emptying the expansion tank. Started to undo the bleed screw and the head sheared off in my hand! Fortunately the rest of the screw wasn't too difficult to remove. There was a little air in there, though.
Just spent an hour in the workshop turning a new screw from black Delrin. I've never tried to knurl Delrin before - it's surprisingly tough stuff.

[ashm]

Good news:
The new thermostat comes with a suitable gasket.

DSC02101 (Small).JPG

Bad news:
Another sheared screw! Arrgh!

DSC02102 (Small).JPG

Any advice? I've tried penetrating oil, heat, mole grips and the rest of the usual options. Next stop is to get a local workshop to weld a nut onto the remaining stud, perhaps?

I've lost track of how many screws and bolts have sheared since I got the car in April...

[Monty]

what about a small set off Stilsons (Plumbers pipe wrench)? remove the old thermostat to give more room.

[dapinky]

Adam,

You can remove the thermostat housing from the end of the engine, which will enable you to get it off the car......

Do you have any Washing Soda (Calcium Carbonate)? (88p a Kilo at Tesco)

If so, put a tablespoon in a gallon of water in a PLASTIC bucket - attach a battery charger (12V) negative lead to the thermostat housing, and a poitive lead to a small ball of steel wool - or piece of scrap steel (not galvanised or stainless). Drop the steel wool into the bucket, but not touching the housing.

Leave it overninght and the rust will have gone from the bolt (or at least, be loosened enough to brush off) and the wire wool will be rusty!

As the housing is aluminium, it will be unaffected by the electrolitic process.

Stud should just unscrew.

Alternatively, with it on the bench you can get at it with an angle grinder (to make a flat side, to get molegrips to have a better purchase) - but worth a go at the electrolysis first!

(The system works a treat for cleaning up old brake discs etc as well!)

(See this site for more of the science behind it - but it works!)