1984 Turbo Esprit overheating after 48 hours of ownership! Seriously worried!

[GreenGoddess]

I finally managed to get to work on the car today.

I got the engine up to temperature and confirmed that the thermostat was working properly by feeling the pipe in the front wheel arch that contains the otter switch. It got nice and hot once the engine temp was showing 90 degrees.

I then decided to open the radiator bleed screw as the engine was still running. It looks as though my car has a nice shiny new silver (aluminium?) radiator fitted and the bleed screw was in a slightly different position to what I expected. I had to access it from under the wheel arch instead of through the front luggage compartment. Anyway, I made a rookie error and removed the screw completely. The water was obviously scorching hot and even with a thick welding gauntlet on I couldn't get the screw back into the hole without getting 3rd degree burns. So all the coolant drained out of the car until it was below the level of the bleed screw. 🤬

I also noticed that the thin coolant pipe that runs from the header tank to the silver curved pipe at the back of the engine bay had been routed underneath the air filter housing. I disconnected it and routed it correctly around the top edge of the engine bay. 

Due to the recent engine rebuild (600 miles ago), the car will have been filled with new coolant. So, instead of going to the hassle of draining the remaining coolant, I just topped it up with 5 litres of concentrated anti-freeze. I made sure the radiator bleed screw was loose as I was topping it up. I also jacked up the rear of the car as high as I dared on a trolley jack as I was filling it up. I also spent about 5 minutes squeezing the hell out of the radiator bottom hose under the left wheel arch. I could hear air gurgling around as I was doing it and the coolant level in the header tank kept dropping. When the coolant level wouldn't drop any more, I topped it up to the correct level and then took the car out for a 30 minute drive. The temperature gauge stayed 1 or 2mm under 90 degrees for the entire journey. I also made sure that the heater was set to hot during the refill and during the test drive.

Lotusfab: I didn't test the temperature gauge as I couldn't find your instructions in your massive blog.

Andyww: I haven't replaced the voltage stabiliser yet, but I have the part ready.

So, I have a couple of questions:

1. Do you think I did everything possible to remove any airlocks?
2. Will it damage the car in any way if the coolant mixture is stronger than 60% as recommend in the user manual? I have no idea what the concentration is now, all I know is that it will likely be very strong (>60% probably).

Edited September 25, 2022 by GreenGoddess

[Andyww]

I had kind of assumed that way back you had bled the rad, as someone did sugggest it, so that alone could have cured it. Vent pipe also would have caused an issue if misrouted. I would say a very good chance its all good now. Dont think the coolant concentration would be an issue.

 

[GreenGoddess]

Thank you. There didn’t seem to be any air in the radiator when I took out the bleed screw so perhaps the pipe I rerouted was the problem. 
I’ll continue using the car each weekend and see how it goes. Thank you for all your help. I really appreciate it 👍😊

[Rambo]

My gut feel is

1. Yes

2. Yes

Edited September 25, 2022 by Rambo
Sp.

[Rambo]

Too strong a coolant can affect heat transfer values 🤔

[GreenGoddess]

God, I’m such an idiot 😞

I just realised that there are different types of antifreeze. I thought all antifreeze was the same. I have filled my car with OAT antifreeze. 🤬

After doing some Googling, I can see that older cars usually use a different type of antifreeze. OAT tends to be for more modern engines. 
 

Am I going to have to drain my car fully and refill the damn thing again? 😭

[esprit22]

An air lock in the cooling system would have been the first thing to investigate! Especially as a non Lotus garage had fitted the radiator/coolant.. 

Completely drain it, refill with the correct coolant, bleed the system properly, then you will have no more issues.

[TAR]

You shouldn't mix the different types of anti-freeze as it can react and cause a sludge to form.

You'll need to drain and flush it generously before refilling with the correct coolant water mix. I would advise using de-ionized water.  

[drdoom]

16 minutes ago, TAR said:

You shouldn't mix the different types of anti-freeze as it can react and cause a sludge to form.

You'll need to drain and flush it generously before refilling with the correct coolant water mix. I would advise using de-ionized water.  

Absolutely.

[GreenGoddess]

🤬🤬🤬🤬🤬🤬🤬🤬🤬🤬🤬🤬

Ok. Thank you chaps. It’s my own stupid fault. You can tell I’m not used to working on cars. 
Do you know which coolant I should be using? The user manual is not very clear and it’s obviously 40 years out of touch with the latest types of antifreeze. 

[drdoom]

The old school stuff, typically greenish-yellow.

[910Esprit]

29 minutes ago, drdoom said:

The old school stuff, typically greenish-yellow.

In the UK, its typically blue!    Any good quality Ethylene Glycol (IAT technology)

Edited September 25, 2022 by 910Esprit

[Andyww]

Completely draining the system is somewhat tricky. Most of it will come out through the rad drain tap which is bottom right at least on the OEM rad, but you would also need to disconnect the hoses under the engine to get it all out. Then the heater might still be full so that would mean disconnecting one of the heater hoses from the engine and route it down under the car so it drains out.

 

[GreenGoddess]

6 minutes ago, Andyww said:

Completely draining the system is somewhat tricky. Most of it will come out through the rad drain tap which is bottom right at least on the OEM rad, but you would also need to disconnect the hoses under the engine to get it all out. Then the heater might still be full so that would mean disconnecting one of the heater hoses from the engine and route it down under the car so it drains out.

 

😫 Do you think I would need to go to such lengths? What about doing a normal drain and flush followed by driving it for 30 minutes with just water in the system, and then another drain and flush before refilling with the proper stuff. Would that suffice do you think? I don’t fancy fumbling around with pipes under the engine and disconnecting the heater matrix etc. Surely driving it around for a while with the heater on with clean water in the system would dilute any residual coolant enough for it not to be a concern. Do you think?

[ekwan]

5 hours ago, GreenGoddess said:

God, I’m such an idiot 😞

I just realised that there are different types of antifreeze. I thought all antifreeze was the same. I have filled my car with OAT antifreeze. 🤬

After doing some Googling, I can see that older cars usually use a different type of antifreeze. OAT tends to be for more modern engines. 
 

Am I going to have to drain my car fully and refill the damn thing again? 😭

You can use OAT on older engines. Just that you have to flush out all that old Glycol based stuff before refilling or the two types will react IIRC.

[910Esprit]

4 hours ago, ekwan said:

You can use OAT on older engines.

It's my understanding that not all OAT's are the same and some versions are definitely incompatible with soldered joints, or possibly yellow metals typically found in older engines, otherwise we'd all use OAT as its effective many years longer.

GG could of course check with the manufacturer for their opinion

[Rambo]

Do NOT use OAT (pink) on older engines as it will potentially destroy seals and gaskets long term. It also has the ability to find the smallest hole or crack and leak. Keep OAT and HOAT technology for more modern engines. 

What you need, as others have mentioned is "old school", IAT ethylene glycol based anti freeze (typically blue or green) And make sure it is added at the corrrct strength. I tend to use concentrate and calculate final strength but it is also cheap enough to buy a hydrometer off EBay or the like. Get one specifically for coolant and not batteries.

But first you must flush, flush and flush again to make sure your system is clean. OAT (pink) and EG (blue/green) coolants are not miscible and will form a sludge ehich can potentially cause a blockage and affect the heat transfer.

Edited September 26, 2022 by Rambo
sp.

[Andyww]

8 hours ago, GreenGoddess said:

😫 Do you think I would need to go to such lengths? What about doing a normal drain and flush followed by driving it for 30 minutes with just water in the system, and then another drain and flush before refilling with the proper stuff. Would that suffice do you think? I don’t fancy fumbling around with pipes under the engine and disconnecting the heater matrix etc. Surely driving it around for a while with the heater on with clean water in the system would dilute any residual coolant enough for it not to be a concern. Do you think?

There is a heater hose accessible from near the air box on the metal pipe clipped to the plenum. If you connected a hosepipe to that with heater on, and block off the metal pipe, that would definitely flush out the heater matrix and would also push water into the water pump and through the engine including the bypass hoses. So doing that and also draining the rad tap might get it all out pretty quickly.
BTW Euro Car Parts (a company I normally avoid) do sell inexpensive 25L containers of deionised water and also sell the blue antifreeze.

[Rambo]

I should also have mentioned that you need to change the older IAT glycol based coolants more often than the OAT/HOAT based systems.

I change mine every 2 years or so, irrespective of mileage. As my cars are on a limited mileage policy this is typically 2-3k per car.

If you use best quality anti freeze and oil and change them on schedule you will never, or very rarely, have any problems with your engine (same goes for cambelt, water pump and associated parts)

[GreenGoddess]

Thanks Guys. I have got the proper antifreeze on order and I will get to work flushing out the car as soon as possible. I am so annoyed with myself. 😡

Thanks for the flushing tip Andy, I will definitely do that!

[GreenGoddess]

5 hours ago, Andyww said:

There is a heater hose accessible from near the air box on the metal pipe clipped to the plenum. If you connected a hosepipe to that with heater on, and block off the metal pipe, that would definitely flush out the heater matrix and would also push water into the water pump and through the engine including the bypass hoses. So doing that and also draining the rad tap might get it all out pretty quickly.
BTW Euro Car Parts (a company I normally avoid) do sell inexpensive 25L containers of deionised water and also sell the blue antifreeze.

Hi Andy, please can you help me find which pipe you are referring to? I have attached a diagram of the cooling system. Is there any way you can highlight or describe which pipe I need to put the hose into? 

[Andyww]

Its not shown on there is its part of heating/AC.
 

 

[GreenGoddess]

54 minutes ago, Andyww said:

Its not shown on there is its part of heating/AC.
 

 

That's perfect! Thank you so much! You definitely deserve a pint of finest ale! 🍺

[Lotusfab]

 If this is the pipe that was routed under the air filter that was a cause of the air in the system. It must not be kinked and allow a direct route for air to escape the system to the header tank. There is no need to stand the car on its nose if this pipe is correctly installed. You must recalibrate the temp gauge. If its reading 60 degrees at 100 degrees this is 40 degrees off! What is the real temp at 90 degrees indicated? The fans should be on at this temp.

 

[GreenGoddess]

I spent all evening in the garage tonight and I think I must have got almost all the OAT coolant out of the car. Annoyingly, the aftermarket (but very nice) aluminium radiator that is fitted to my car has a drain plug that was impossible to get at without removing countless pieces of the vehicle. I opted to carefully drill a 12mm hole in the fibreglass underside to allow easy access with the required hex key. That will make future coolant changes much easier. 
 

Andy, your tip about disconnecting that pipe and inserting the hose seemed to work an absolute treat! It took quite a while but the water eventually ran crystal clear. I made sure the heater control was set to hot. 

I then refilled the coolant system with 100% water. I am going to leave it like that until the weekend, then I will drive the car for half an hour so that the water has fully circulated and diluted every last drop of any remaining OAT coolant. Finally, I will drain the system and refill with the proper IAT coolant at a 40% concentration and make sure there are no airlocks. 

QUESTION: Do you think that should do it? 🙏

Lotusfab: The thin rubber hose that goes to the top of the header tank was the one that had been incorrectly installed. It had been put underneath the air filter housing so there was a definite U shaped dip in the hose, but it wasn’t kinked. I re-routed the pipe properly yesterday. 👍