Coolant Level Increasing

[BigTed234]

After a 40 mile run on Saturday I went to get some stuff out of the boot and noticed the coolant level was about 3cm above max, and the pressure cap on the expansion tank was slightly hissing. The engine temps were running normally on the run at about 85 to 86 degrees.

 

Anyway, checked from cold this morning and the coolant remains well above max, when it normally behaves itself and hovers just above min. A mechanic I know pressure tested the coolant system today but found no evidence of leaks. While the engine was running there were no variations in the pressure either which the mechanic suggested meant there was no air trapped in the system. There doesn't appear to be any oil in the expansion tank or creaminess in the oil. He then suggested that I was overly paranoid about HGF. Which is probably true.

 

Any ideas where this coolant is mystically appearing from??

 

Cheers,

 

Ed.

[Martin R]

Funnliy enough i was talking with Steve-n who had the same on his Stelvio trip. I cant see how it can be anything other than air locks or a dodgy thermostat. I would try bleeding the sytem anyway. I would also change the pressure cap if its hissing. It should only hiss if you have

 

1) excessive pressure / coolant in the system

2) Its knackered.

[Steve J]

Before you change the cap, take the rubber sealant ring off from under the cap and put back upside down. Often solves slight pressure leaking due to a poor seal.

[BigTed234]

I cant see how it can be anything other than air locks or a dodgy thermostat.

 

Thanks for the reply Martin. I can understand how the coolant level would be increased if there was an air lock in the system, but could you explain how the coolant level would increase if the thermostat was dodgy as it's is still a couple of cm above max even when cold?

 

Cheers,

 

Ed.

[Martin R]

Thanks for the reply Martin. I can understand how the coolant level would be increased if there was an air lock in the system, but could you explain how the coolant level would increase if the thermostat was dodgy as it's is still a couple of cm above max even when cold?

 

Cheers,

 

Ed.

 

Ed, having thought about it some more probably not. As i see it in the system you have a water pump, thermostat, coolant and possibly some air. Is there not also a small valve in the inlet manifold ? I think its commonly called a jiggle valve. I think it works as a self bleeding system. Its a ball bearing in a hole IIRC.

 

I personally would try the following. Get a new cap, for a £5 or so its not worth messing about. I changed my coolant for OAT stuff about 2 years ago and bleed the system as follows.

 

Lotus recommend you pressurize the system to bleed it properly. I presume this is due to the rad being at the front as opposed to the normal K series configuration.

 

I used a Gunnerson Ezi bleed from Halfords to do this. Its for bleeding brakes but works on cooling systems as well. It comes with a variety of cap sizes and one fits the Elise expansion bottle.

 

I dropped the pressure in the near side rear tyre to about 15 psi as you dont want to blow the pipes off. Attach the cap from the Ezi bleed to the top off the expansion bottle. Pressurise the system by attaching the other end of the Ezi bleed to the tyre. If the level drops significantly refill the header tank.

 

Undo the bleed screw on the radiator outlet pipe. Its under the N / S front wheel arch liner. You can get at it by peeling back the wheel arch liner. You may want to remove this first to make it easier though. Tighten the bleed screw when water comes out. Dont undo it too far.

 

Slowly undo the bleed screw on the engine coolant rail till water comes out as well.

 

Remove the Ezi bleed at this point. With the header tank cap removed start and run the engine at idle till the temperature guage reads 60 - 65. Increase engine speed to about 2000 rpm. If you watch the temp guage as it rises you should notice the temp drop back as the thermostat opens. With mine it was at about 85 but i expect they all vary slightly. After its done this twice, rebleed at the radiator bleed screw with the engine still running.

 

Continue to run the engine at 2000 rpm till the radiator return pipe feels hot. At this point replace the header cap. Run the engine at 2000 rpm till the fan cuts in. Let the engine and coolant cool fully and top the tank up to the normal level. I top mine up to just before the min mark.

 

Dont forget to pump the tyre back up. Hope this is of some use.

[chorton_1]

I used a Gunnerson Ezi bleed from Halfords to do this. Its for bleeding brakes but works on cooling systems as well. It comes with a variety of cap sizes and one fits the Elise expansion bottle.

 

 

I didn't know that.......and its useful to be aware of if you're trying to find leaks!

[Tango190]

Slowly undo the bleed screw on the engine coolant rail till water comes out as well

 

 

Where the hell is that Martin ??

 

Photo ??

 

 

75 is loosing coolant and think inlet manifold side - plastic inlet manifold seal

 

Can see some evidence of water leak on head casting and SMELL

[Martin R]

Bob, i will post a pick tomorrow. I dont know if the 75 is the same though. Dragged from the back of my mind, the inlet manifold has a o ring seal as well. The early ones are black but the later improved ones are Green then dark Green. The dark green one is the best IIRC but you will have to confirm this.

 

Bob, ive done a pic but my internet connection at home is down. I will upload it as soon as poss. The coolant rail comes from the back of the thermostat housing on mine. About 18 inches behind this is the bleed screw. On yours with the engine in the right way i would expect it to be on the O / S rear of the engine. I am going to take the inlet manifold off my head at the weekend hopefully ( time permitting ) If i do i will post a pic of that as well.

[Tango190]

Thanks Martin,

 

It's difficult to see at the back of the engine, I know when it had a new thermostat fitted when I first bought it the guy was going mental due to the poor access.

 

Certainly getting some odd startup experiences - like a couple cylinders not firing - then after couple of seconds all is well - maybe water weeping into the cylinder or could be electrical.

 

Either way its loosing water and you can smell the damned antifreeze from under the bonnet.

 

Bit of a post against the thread name - but its not coming out of the rad cap I'm sure.

 

Temp guage always reads bang on normal - but the 75 guage is known to be less than helpfull !

 

Wondering what kind of job it is to change the inlet manifold gasket as a starting point - just I'm getting crap at the spanner work these days - lol

 

Awaiting your piccy.

 

Ta

[Martin R]

Here you go Bob. The coolant bleed screw on the rail can be seen in this pic. Its a bit clearer as the head is off and on the work bench waiting for DVA. I dont know if it will be the same as on yours. I will post a pic of the inlet manifold once ive had the time to drop it off.

 

[Tango190]

Thanks Martin - wow - so many pipes and wires

 

Will have to wait for the inlet mani piccies to se what you mean about the seal .....

 

Engine was changed, just wonder if they never fitted new gaskets on the manifold etc

 

Known problem on 75 1.8 K Series is the inlet manifold gasket leak (non Turbo)

?

 

hence my uncertainty of the problem.

 

I.E. I never heard that problem in the Elise world ??

[Martin R]

Bob, the inlet manifold leaking is not uncommon on Elises. Not as common as the HGF but not unknown. I will post the pic in the week.

[Tango190]

Bob, the inlet manifold leaking is not uncommon on Elises. Not as common as the HGF but not unknown. I will post the pic in the week.

Ta

 

No oil in water - no water in oil

 

Sure the leak is on the mani

 

£120 new battery today to take away the electrical probs - Banner battery was dud

 

Still stumbles on cold start - but starts fine when hot

 

HGF usually goes the other way round

 

Really bugging me now as I know the engine was a recon and still sounds sweet when warm

 

GRRRRRRR

 

Sure its pissing coolant into the cylibder and needs to burn it/ push it out under compression

 

LOL

 

Deluded HGF person me ....

[MartinQ]

I had a similar problem (well, apart from the coolant level increasing).

My car was garaged for 2 weeks while I went on holiday. On returning, the battery was flat and with no jump leads, called out the AA. After it was started, there was a misfire for a few seconds and steam was coming out of the exhaust even when it was hot and the temp quickly went up to 110C. This was quickly solved with bleeding the coolant system - the radiator bleed screw can be reached by removing the plastic cowling around the radiator and reaching down behind the nearside front wheel - so it's not necessary to remove the wheelarch liner. There was also air in the heater matrix which was sorted by removing the pipes until just water flowed out.

As steam was still coming from the exhaust (and me checking, and rechecking the oil and coolant for mayo due to HGF paranoia), the AA guy diagnosed a dodgy inlet manifold gasket. He said it's pretty common on the k series. I was just relieved it wasn't HGF. Yet.

[Tango190]

Well that is starting to sound very similar - I was on the route of changing the pencil coil packs but maybe Martins piccie of the manifold gasket will allow me to investigate further.

 

Cheers for that post 100