Losing Coolant

[EM One Hundred]

Last fall, I got stuck in a terrible traffic jam and my car overheated and while I was able to shut it down and get off on a side street I blew a lot of coolant out. I refilled it with 50/50 mix and continued on the trip I was on but started having the coolant blow out on long climbs up mountain passes. Driving on level ground seemed fine, so I became very watchful of the temp gauge and when it started to rise, I would pull over and let things cool down then top up the coolant. I did this successfully for about 600 miles but on the last leg toward home, I was refilling every 30 minutes or less with plain water just to get home.

Over the winter, my mechanic did a leak down test and checked all systems. He found two culprits: A thermostat that was stuck with only about 1/16th of an inch open and the fan temperature sensor not sending a signal. In addition to fixing these two things, I had him replace all the hoses, belts and even the timing belt and water pump per the WikiLEC instructions. After all that work we found we still had a problem with the fans not operating and after a third sensor and checking all fuses, relays and wires, we determined that a manual fan switch was the best solution. Once he had wired in a manual switch he let it run for almost an hour and the temp never went up beyond the ¼ mark as it had always done before.

I thought I was in the clear but today I find I am not. The car is still losing coolant and the temp gauge is fine with the fans running until it gets down about two quarts and then the temp starts going up despite the fans. If I fill the system again it is fine for a while then repeats. I am stumped and so is my mechanic. I should mention that the car runs great with lots of power and good fuel mileage so other than this issue everything is great!

I am beginning to think there is a head gasket issue that we did not find when the leakdown test was done. Is that possible? Something is pushing out the coolant and I don’t know what. Has anyone else had a similar problem and found something that we have overlooked?

[steve matthews]

how many miles?

[Rambo]

Sounds like you are getting combustion gases in the coolant.

Maybe your mechanic missed something when he carried out the combustion leak/sniffer test ? Probably worth doing again as it's very simple to do via the header tank and/or radiator. It will detect leaks in the head gasket, cracked blocks or cracked and warped heads

My suspicions lean towards HGF or imminent HG failure too. Things sound far from normal

[GeoffSmith]

Check/change the radiator cap Ross. Mine was occasionally mildly incontinent at one time and it was down to the pressure relief valve not operating - I diagnosed it by pressurising the system manually.

[esprit888]

When you say 'I blew a lot of coolant out' where exactly was it visibly noticeable and what was the engine temp at the time? Radiator cap, header tank cap or exhaust? Also its not unheard of to have a duff thermostat right out of the box. All signs point to a HGF but knowing where its blowing out would help to diagnose.

[EM One Hundred]

Thanks for the input from all of you Here are the answers to your questions:

1. Mileage is 56,800 Why is that a concern?
2.Radiator cap (the one on the coolant tank at the firewall) is snug but not really tight. If I tighten it any more it slips a thread and I start all over tightening again.
3. The coolant always boils out of the top of the coolant tank so Geoff may be on to something. The gauge showed full hot before I could get off the road and shut it off. After it blew coolant was all over the engine bay so tracing the exact path was fruitless. Since the new thermostat was installed the temp comes up to just over a quarter on the gauge then goes down to just below a quarter very quickly when the thermostat opens, or at least that is what I think is happening to make the gauge move like that.
4. Rambo: I fear you are right but I will try a new cap first in the hope that the cap will solve it.

By the way, this is a Federal car which seems to be different in the way the cooling system lays out from UK cars. I looked for the bleed screw behind the headlight pods just to see if I could eliminate an air pocket but found nothing that looks like the photos I saw on this site. Also, I am not a strong mechanic, I know just enough to be dangerous and also my limits so I know when to take it to my mechanic!

[dapinky]

My first thing to do would be replace the coolant tank cap - if it isn't getting a good seal then it will not allow the system to pressurise at all, and so the coolant will boil at 100C, and not go to 110C (or whatever the pressure rating - 1.2 bar - of the cap allows), and the coolant will come out of the loose seal between cap and tank.

The cap doesn't have to be a Lotus part - it is a standard Vauxhall (GM) part, with many aftermarket options...... at least, there is lots of choice in the UK.

I used a Febi Bilstein 01211, which (according to Amazon.com is available in the USA) - and the advert lists lots of cross references which may assist you.

If this doesn't sort the issue, it will at least pressurise the system and force the water out of somewhere else!

Cross-reference for this item:-

Make and model this part will fit
Vauxhall Agila I, Astra II, Astra III, Astra IV, Calibra, Calibra 4x4, Carlton II, Cavalier III, Cavalier III 4x4, Corsa I, Corsa II, Frontera I 4x4, Meriva I, Nova, Omega, Tigra I, Tigra II, VX, Vectra I, Zafira I
GM/Opel Zeichnungsnr.
Daewoo Espero, Nexia
Opel Agila A, Ascona C, Astra F, Astra G, Calibra, Combo B, Combo C, Corsa A, Corsa B, Corsa C, Frontera A, Kadett C, Kadett D, Kadett E, Meriva A, Omega A, Omega B, Senator B, Speedster, Tigra A, Tigra B, Vectra A, Vectra B, Vita, Zafira A
Saab 9-3 I, 9-5 I, 900 II
Orginal Manufacturer part number this item will replace (OE Number)
Daewoo: 90409256
GM/Opel Zeichnungsnr.: 90467473, 90352470, 90409256, 90409257, 90410326, 90467472
Opel: 13 04 666, 13 04 659, 13 04 660, 13 04 661, 13 04 665, 13 04 667, 13 04 853
Saab: 43 95 513, 43 56 700, 43 567 62, 43 567 70
Vauxhall: 90467473, 90352470, 90409256, 90409257, 90410326, 90467472
Other Manufacturers equivalent part number
Borg & Beck: BRC68, BRC106, BRC132
First Line: FRC68, FRC106, FRC132
Gates: RC201, RC235
Metzger: 2140039
Meyle: 614 800 9001
Topran: 202 261
VAICO: V25-0550, V40-0480, V40-0480-1

[Rambo]

2.Radiator cap (the one on the coolant tank at the firewall) is snug but not really tight. If I tighten it any more it slips a thread and I start all over tightening again.

Oh oh. You never mentioned that before. Logical place to start for a few $$'s and 15 secs work

[esprit888]

As the Pink guy says, the cap needs to seal in order to pressurize the system and raise the boiling point, along with anti-freeze (as water boils at a lower temp/pressure than anti-freeze) Also only fill it to the line, don't fill it to the neck as there is no room for expansion, if memory serves on the OEM header tank there is a line where the strap wraps around with the words 'Kalt' on it which is an indication of where the part was sourced as that's 'Cold' in German. Federal cars do not have the bleed screw behind the LH headlight pod, no idea why, only thought would be due to the different crash structure and front clam on federal cars so its a run and burp process.

[GeoffSmith]

…Also, I am not a strong mechanic, I know just enough to be dangerous and also my limits so I know when to take it to my mechanic!

You're too modest - you know enough to get you out of trouble when you're halfway through a 1000 mile odyssey to the arse end of beyond.

[steve matthews]

Mileage is 56,800 Why is that a concern?

Thats not a lot of miles for HGF unless abused in the past.

[EM One Hundred]

Geoff: I am comfortable with 50 year old cars as they are quite simple...this M 100 is most certainly not! I think I need the Elanscan software.

Steve: I don't think it has ever been abused as I know both previous owners and they took excellent care of it. I hope the lack of pressure cap is the problem.

I have purchased a replacement tank and cap as the cap I got from AutoZone that matched one of the cross reference numbers would not tighten either so the threads on the tank may be buggered. I hope the complete set will solve things.

Thanks for all the good information and a path to a solution. The wealth of knowledge here is amazing!!

[Rambo]

As we say over here, "two heads are better than one" Or, in this case, four or more. And I' m not talking cylinder heads.

Just another thought. I take it you've checked out the radiator? No leaks or blockages ie no sludge build up. If so, it might be worth flushing well with water and pressure testing again.

[EM One Hundred]

Well I am out of things to try short of the head gasket. Here's what happened in the past ten days:

1. Found a cap from the cross reference list Dapinky shared, installed it but it would not tighten either. It would get snug then slip a thread. Returned it and

2. Ordered a replacement tank and cap combo. Installed it and discovered the tank that was on the car before was NOT original so a bracket and hose extension had to be removed for the install of the one I just bought.

3. Filled the system with coolant mix (50/50) and tried to burp the air out.

4. took it for a short drive (five miles) and checked everything. It looked fine...coolant level just as I filled it, temp gauge not moving up, no coolant smell.

5. Yesterday I went for a longer drive and pushed it a bit up some hills and the temp went up a bit but not more than half on the gauge until I came up the long hill to my home when the gauge went up quickly and I could smell coolant. Pulled into my garage and the coolant vapor was visible from the back of the bonnet and the smell of coolant was strong. Opened the bonnet, the cap had blown completely off the header tank and was down in the engine bay, no coolant in the tank and a mess everywhere.

6. I'm TOAST! It looks like a complete removal of the head for a gasket replace and check the head for warping as well.

[esprit888]

Somethings very wrong, Not doubting you tightened the cap but when it is correctly screwed on and tightened I have never heard of the system building sufficient pressure to blow a cap past the threads because when its on there its damn tight and the vent or a hose would typically blow first (the cap is designed to vent at 17.5 Ilbs, nowhere near enough to blow the cap past the threads on the tank). Can you confirm the cap is correct (vented) and was real tight on the tank? the pressure required to blow it off would be extremely high, I cant even guess how high as I have never heard of this before. Also as per previous comment the tank must NOT be filled to the top, it should only be filled approx. halfway, where the strap usually sits and there is a KALT sign with an arrow to show the cold level.

[EM One Hundred]

Esprit 888 You are right...something is very wrong!

I filled the reservoir to the midpoint leaving the upper half for expansion as I was told by you (even though I knew that already) then screwed the cap on very tightly. It worked at first as it was supposed to but under real load it went kerblammo! I am as surprised as you are that it happened. I am not completely incompetent and you are not here so please believe what I am reporting.

Is there any other way that much pressure could build up in the cooling system?

[esprit888]

Don’t believe I called you incompetent, I actually said ‘ I don’t doubt you’, simplest way to confirm a HGF take it to a garage that has a combustion gas sniffer or buy a test kit off Amazon/ eBay that detects combustion gases in the coolant.
https://www.amazon.com/UView-560000-Com ... 346&sr=8-4

[Rambo]

Esprit 888 You are right...something is very wrong!

I filled the reservoir to the midpoint leaving the upper half for expansion as I was told by you (even though I knew that already) then screwed the cap on very tightly. It worked at first as it was supposed to but under real load it went kerblammo! I am as surprised as you are that it happened. I am not completely incompetent and you are not here so please believe what I am reporting.

Is there any other way that much pressure could build up in the cooling system?

I'm not there either but you haven't confirmed whether the radiator is blocked or you have potential or actual HGF as previously suggested.

I'd suggest trying a different mechanic

[dapinky]

I would expect one of the hoses (or joints/clips) to blow apart before the cap would blow off the reservoir, so I would suspect a very sudden pressure increase, over a gradual one, and possibly localised to that part of the system........ has the thermostat been checked/replaced recently?

[Rambo]

@Dapinky - thermostat apparently checked out - see OP. My worry is that driving with all that coolant loss and high temps will seriously have f------d the head and engine