Cooling System

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KLM
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Cooling System

Post by KLM »

Hi

I feel I have a circulation issue on my 1990se.

temperature only goes up to about 70 and the header tank begins to bubble. I have removed the thermostat and tested it in a jug of boiling water and watched it open. I have removed top hose from thermostat and blown down it to see if rad is blocked. I also gave all the heater hoses a good squeeze and I can see coolant coming from thermostat housing. so I don't thin I have a blockage.

the top hose gets hot pretty quick but bottom hose of rad doesn't get hot at all. engine was rebuilt couple of yrs back but I am suspecting water pump ?

Kind regards

Pete Boole
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Re: Cooling System

Post by Pete Boole »

How old is the rad?

Pete

KLM
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Re: Cooling System

Post by KLM »

the rad is about 3-4 years old

I think tomorrow I will remove the top hose from the thermostat and turn the engine over , if it sprays coolant out I can assume pump works ?

KLM
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Re: Cooling System

Post by KLM »

I have filled up header tank with new red coolant and ran car then removed various hose and the new red coolant is clearly getting around the system, heater is set on warm/vents/full on and it is blowing hot enough.

so I think everything is fine.

the problem arose from when I found the hose from the thermostat to inlet manifold leaking, btw what a pita it was to tighten the jubilee clip up under the carb.

anyway It must of got air in when I did that and forgot to purge it.

Pete Boole
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Re: Cooling System

Post by Pete Boole »

Sounds like you've sorted it :D

Pete

Sirclip
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Model: Excel Celebration
Colour: Marque Lotus
Year: 1991
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Re: Cooling System

Post by Sirclip »

Hi KLM,
I see in your post that you mentioned that the anitfreeze was "red coolant". In general (but not always), red coloured coolant/corrosion inhibitors are of the 'OAT' variety, which I believe is not suitable for our cars. The type of antifreeze that's suitable are 'silicate based' products, which are (generally) blue in colour.

Halfords sell a suitable product (which is Blue).

Here's a very good write up on the subject from the MG owners Club dating back some years. https://www.mg-cars.org.uk/imgytr/hints ... freeze.pdf

Based on this, I'd suggest that you drain and flush your system and replace with some Silicate coolant, you'll need around 4 litres, then ideally fill with deionised water (approx 4 litres). Sorry if this isn't good news, but I hope to have helped. :)

KLM
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Re: Cooling System

Post by KLM »

Hi

one thing I noticed the other day was slight wisp of vapour coming the face of the radiator that faces the engine, I assumed this was coolant evaporating from when I had removed the top hose at the thermostat and had splashed onto the rad.

however I have just ran the car again to check my temp sender and its doing it again. there seems to be 3-4 small patches where the rad looks damp with wisps of vapour coming from it. it looks like I might need a new radiator. :roll:

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Lotus-e-Clan
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Re: Cooling System

Post by Lotus-e-Clan »

KLM wrote:Hi

one thing I noticed the other day was slight wisp of vapour coming the face of the radiator that faces the engine, I assumed this was coolant evaporating from when I had removed the top hose at the thermostat and had splashed onto the rad.

however I have just ran the car again to check my temp sender and its doing it again. there seems to be 3-4 small patches where the rad looks damp with wisps of vapour coming from it. it looks like I might need a new radiator. :roll:
Most of my radiator issues over the years have been leaks from where the rad fins join the side tanks - caused by road /engine vibration of the rad (ie too tightly mounted /not properly rubber mounted) - plus one crushed top hose brass tail - caused by over-tightening the Jubilee clip.

Best to make sure your (new / re-cored) rad is properly rubber mounted.
Peter K

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Tanz
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Re: Cooling System

Post by Tanz »

When I had my rad re-cored 8 years ago, I had it made a couple of mm narrower. Fits easier and I have had no leaks since. Was a bit worried at the time that going away from the Lotus design might cause a problem. They must have made it a tight fit for a reason. Some say to add strength to the front of the body but I cant imagine anyone using a radiator as a strengthening means.
Cheers, Phil
Never take life seriously, nobody gets out alive anyway!

KLM
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Re: Cooling System

Post by KLM »

Hello

Well, I have just heard back from the garage who has tested my radiator. its totally blocked and goosed.

so I am looking for a new one.

Does anyone have any recommendations? also what are the alloy one from china on ebay like ?

Kind regards

KLM
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Re: Cooling System

Post by KLM »

There is a highly experienced outfit about 15mins from where I live so I think tomorrow I will take my old one to them for a look/quote.

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amarshall
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Re: Cooling System

Post by amarshall »

KLM wrote:Hello

Well, I have just heard back from the garage who has tested my radiator. its totally blocked and goosed.

so I am looking for a new one.

Does anyone have any recommendations? also what are the alloy one from china on ebay like ?

Kind regards
search.php?keywords=winner+radiator&ter ... mit=Search
https://www.lotusexcel.co.uk/
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KLM
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Re: Cooling System

Post by KLM »

hello

Another twist in the saga.

I picked up my rad from the garage who said it was blocked, he admitted he hadn't pressure tested it. he made his diagnosis on the weight of the rad, he said it was really heavy and so must be blocked.

Anyway I was off to some radiator place 20mins away for them to look at it and quote me for a recore if needed.

I left it with him and he rang back later with the results of the flow test and pressure test.

the radiator is fantastic , really good results and absolutely nothing wrong with it. He did admit he thought it was heavy himself but he has now put it down to the copper/brass internals and the quality of it.

Just to let you know in case anyone is thinking about a replacement ect , I bought it as a refurb from lotus-bits about 5 yrs ago, so a big thumbs up from me.

Also I wanted to check the impellor on the water pump but didn't want to remove it as the car is on ramps to get rad out and the power steering pump is accessed via the passenger wheel so it was going to be a buggar of a job. so I bought this-


https://www.amazon.co.uk/gp/product/B01 ... UTF8&psc=1

Now I wasn't expecting much with it being just £10 and free next day delivery , however once I turned my phone display up to max and set the device to max and got rid of the coolant in the pump, it was surprisingly very good, I could clearly see the blades and I could just about rotate it with the belt still on to see it turning ect.

A handy little device that saved me a lot of hassle.

so I now know I have a good pump, a good thermostat, a good radiator. I have also flushed the engine and the last of the coolant came out followed by clear and clean fresh water.

I know the heaters work well and the top and bottom rad hoses get hot . so I cannot think why there could be an issue.

KLM
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Re: Cooling System

Post by KLM »

My cooling saga continues.

So, I was convinced I had a cooling issue, where as the gauge wouldn't get to 90c it stayed around 70 but the water in the header tank was beginning to boil. which lead me to think it was a circulation issue. so I have had the rad tested which is good, the thermostat I tested and appeared to work fine in a jug of boiling water, the water pump looks fine.

when I refitted the rad I wanted to make sure the system was totally free of the previous coolant as I was going from pink stuff back to green/blue so I filled the system with just water ran it for a bit and low and behold gauge went up to 90 and header tank was fine. I though great.

so then next day I dropped the water and refilled with coolant/water. I also put in a new temp sensor and a new stat and it is back to going up to 70 on gauge but header tank is 100+

I redid it again this morning, I dropped all the coolant into a clean bucket and put back in, I slackened of the hose at back of engine and set heater to hot and put fans on full. and it still does it.

what am I doing wrong ?

KLM
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Re: Cooling System

Post by KLM »

I also put in the thermostat that I had in, which does appear to be slightly different to the one sj sportcars sent me which should of been the 82c one. either way it does on both. I also have refilled it whilst on the ramps.

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