Lotus Elan

Heat problem

PostPost by: StephenT » Tue May 23, 2023 5:04 am

I picked up a ‘66 Series 2 project last year. The car has not been driven since 1976… until yesterday. Now I can really begin to identify the cars needs. The first thing that has come to light now that the car is drivable is an over heating issue. The car will idle for 20 minutes and the temp gage sits steady at 160*. But when driving for just a few minutes the temp starts to climb to the point of overheating. Today I flushed the radiator and block. After refilling the system I let it idle for a long time and again it held steady at 160*. After driving for a few minutes the temp started rising again, although slower than before. I stopped driving when the temp hit about 200*, I didn’t shut off the engine but let it sit and idle for another 15 minutes and the temp dropped back down to around 190*. The radiator is the original brass unit with two 9” electric fans mounted on the front pushing air through the rad. My guess is the old radiator is fine at rest but can’t handle the extra heat of an engine under load. Am I missing something, any advice from the experts here would be appreciated.

Thanks,
Steve
StephenT
First Gear
First Gear
 
Posts: 49
Joined: 09 May 2022
Location: Southern California

PostPost by: rgh0 » Tue May 23, 2023 5:52 am

I would check

1. Are the fans switching on and at what temperature ?
2. Is the thermostat fully opening and at what temperature ?
3. Is you temperature gauge accurate ?

A presurised system with antifreeze coolant will not boil until above 230 F.

cheers
Rohan
User avatar
rgh0
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 8940
Joined: 22 Sep 2003
Location: Melbourne, Australia

PostPost by: StephenT » Tue May 23, 2023 6:38 am

I am assuming the thermostat is opening fully but not sure how to measure that. When refilling the radiator I had the engine running. When the gage hit 160* the level in the radiator began dropping so I could add more fluid. I am pretty sure that is when the thermostat opened. So that would signify the gage and thermostat are working correctly.

I am wondering if by mounting the fans on the front of the radiator could they actually be blocking more air flow than they are creating when driving? Two 9” fans pretty much cover the radiator. I don’t think I have enough room between the radiator and the water pump pulley to mount the fans behind the radiator. I will check tomorrow.
StephenT
First Gear
First Gear
 
Posts: 49
Joined: 09 May 2022
Location: Southern California

PostPost by: StephenT » Tue May 23, 2023 6:42 am

I guess I could drop the thermostat in a pot of hot water and watch it open to verify it is opening all the way.
StephenT
First Gear
First Gear
 
Posts: 49
Joined: 09 May 2022
Location: Southern California

PostPost by: Ianashdown » Tue May 23, 2023 6:45 am

Just remove the thermostat to be sure it not part of the problem.

Ian
SoCal
Ianashdown
Second Gear
Second Gear
 
Posts: 215
Joined: 14 Oct 2022
Location: Orange County, USA

PostPost by: StephenT » Tue May 23, 2023 6:47 am

I forgot to mention that the fans are just hooked up to 12v and run all the time. I have the parts to install a thermostat for the fans but have not installed them yet.
StephenT
First Gear
First Gear
 
Posts: 49
Joined: 09 May 2022
Location: Southern California

PostPost by: types26/36 » Tue May 23, 2023 7:23 am

Have you checked that fans are actually pushing the air through the radiator and not sucking? Could the fans be turning the wrong way? Some fans are designed as pushers and some as suckers and by just reversing the rotation they are not always as efficient.
Just by flashing a radiator it does not always clean it out, sediment can build up and block the tubes and it needs to be cleaned or recored by the proffionals.
Brian
64 S2 Roadster
72 Sprint FHC
User avatar
types26/36
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 3887
Joined: 11 Sep 2003
Location: U.K.

PostPost by: rgh0 » Tue May 23, 2023 7:32 am

Mounting the fans infront or behind makes no difference and will not block air flow espcially if running all the time anyway. Check that the fans are actually blowing through the radiator

cheers
Rohan
User avatar
rgh0
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 8940
Joined: 22 Sep 2003
Location: Melbourne, Australia

PostPost by: lotusfan » Tue May 23, 2023 11:02 am

Stephen

I agree with both Brian and Rohan. Check that the fans are actually blowing through the radiator by seeing if a piece of thin paper will stick to the front of the fan, it is sometimes difficult to determine airflow direction just using your hand.

If the airflow direction is correct then the radiator is probably partially blocked internally and needs recoring.
Mike
72 Sprint DHC
User avatar
lotusfan
Third Gear
Third Gear
 
Posts: 381
Joined: 15 Sep 2003
Location: S Bucks, UK

PostPost by: elanner » Tue May 23, 2023 11:39 am

From an old Hagerty article:

https://www.hagerty.com/media/maintenan ... ing-issue/

"The answer here depends on how the car is running hot. If it’s hot even while cruising down the highway, it’s a water-flow issue. If it’s cool while in motion and only hot while idling in traffic, it’s an airflow issue."

Of course, if the fan is running backwards I guess this would be turned upside down....

Nick
User avatar
elanner
Fourth Gear
Fourth Gear
 
Posts: 621
Joined: 14 Sep 2010
Location: Boston, MA, USA

PostPost by: joe7 » Tue May 23, 2023 12:24 pm

Had this problem one time. After a short drive it would overheat, let it idle and it would cool down. Found out it needed new bearings.
joe7
Second Gear
Second Gear
 
Posts: 173
Joined: 09 Oct 2013
Location: USA

PostPost by: 2cams70 » Tue May 23, 2023 12:43 pm

joe7 wrote:Had this problem one time. After a short drive it would overheat, let it idle and it would cool down. Found out it needed new bearings


What needed new bearings?? I'm presuming not the engine!!

Renew the thermostat as a matter of course. They are cheap. Do not run without a thermostat. I hope you renewed all the rubber hoses, fan belt and radiator cap as a matter of course also.

Check that the ignition timing isn't retarded. Engines run hot if the timing is too far retarded.
Run it with some coolant flush in the system. Do it a couple of times. Drain and refill with correct coolant.

Provided the system isn't leaking or boiling it doesn't seem like there's much of a problem,
1970 Ford Escort Twin Cam
1972 Ford Escort GT1600 Twin Cam
1980 Ford Escort 2.0 Ghia
Peugeot 505 GTI Wagons (5spdx1) (Autox1)
2022 Ford Fiesta ST.
2cams70
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 2178
Joined: 10 Jun 2015
Location: Australia

PostPost by: wotsisname » Tue May 23, 2023 1:23 pm

An easy check for the sender/gauge. - drop the sender in water, with wiring attached ( the earth is trickiest, but a crocodile clip is useful). stick it in a pyrex beaker, or an old tin can and heat to boiling (hot air gun works a treat).. what does the gauge show ?
I had a similar issue which turned out to be the (old) sender unit.
1968 Elan plus 2 - project
2007 Elise S2 [modified with a Hethel 70th sticker (yellow)]
2000 Elise S1 - Sold
wotsisname
Third Gear
Third Gear
 
Posts: 487
Joined: 24 Jun 2015
Location: Hertfordshire, UK

PostPost by: Ianashdown » Tue May 23, 2023 1:33 pm

2cams70 wrote:
joe7 wrote:Do not run without a thermostat.


I was only suggesting to remove the thermostat for the purpose of testing and eliminating it as the source of the problem. However the only downside to not running a thermostat is the longer required warm-up before driving.

We always remove the thermostats from racing engines, but they are thoroughly warmed up before being driven.

Before replacing the radiator you could try having your cleaned internally with an ultrasonic cleaner.

Ian
Ianashdown
Second Gear
Second Gear
 
Posts: 215
Joined: 14 Oct 2022
Location: Orange County, USA

PostPost by: pptom » Tue May 23, 2023 2:06 pm

Mine had sat for 20 years, stripped the engine without even attempting to start it. The inlet pipe to the waterpump was completely blocked / crystallised up and the block was full of sludge and hard rust deposits which a flush wouldn't have removed. Engine shop pondered sending it for an acid dip, but it got blasted out in the end.

Also a couple of freeze plugs were well past their best, I was certainly glad I didn't attempt to run it.
pptom
Second Gear
Second Gear
 
Posts: 106
Joined: 31 May 2018
Location: UK, Northampton
Next

Total Online:

Users browsing this forum: Dan in NJ, stugilmour and 19 guests