Overheating when idling/crawling traffic

[TREVORGIDLOW]

I have a 2.1 Pinto. Fan, coolant, thermostat OK. Not bonnet vents.

 

Runs at around 80deg at normal speeds. When idling or in crawling traffic 5mins and it's up to 100deg+ if I let it. I know pinto's run hot, but need to resolve. I'm a learner on things mechanical (purchased, not built). But logic tells me that when the car's still there's no pressure at the nosecone, so high temp air tries to escape via the nose cone and therefore gets pulled through the rad - Catch 22. 

 

It would seem to make sense to block off the gaps between the rad and the nosecone so that it can only pull though coll air, but how would I fix aluminium sheets to the rad itself and would i need some sort of rubber flanges to seal small gaps effectively. 

 

Another option would seem to be to cut some bonnet vents, but reluctant to do this because I've read that it weakens the boonnet and generally looks naff.

 

I have wrapping on the exhaust manifold, but it's could be done better, there are some gaps. I would also be interested to know what there general opinion is on wrapping, I read some horror stories about overheading the manifold and heads causing damage, is this valid for someone who doesn't track car but drives 'in a spirited fashion' most of the time   , but only up to say 6000rpm on this engine. OTT or genuinely to be avoided? Are the performance gains negigable?

[Man On The Clapham Omnibus]

When I bought my Pinto it did exactly that. In my case it was because the builder (not me, sadly) had mounted the fan so that it sucked forwards through the rad where it should have either blown through from the front or sucked from behind. Once I corrected that and still had a slight overheat problem, I had the usual Pinto battle with air-locks. If you think you have an airlock - feel the hose and see if there's a cool one or the top hose into the rad is cool at the top half and hot underneath. Advice on bleeding is out there in the forums but if the search facility fails you there will be advice available. You do have a fan, don't you?

[Welly Jen]

With a good fan that is fitted the correct way round, a good radiator and all the air locks out a Pinto engined car can be fine for cooling. Mine has no exhaust wrap, no extra bonnet vents, no ducting around the radiator. It uses as a Polo radiator. In a traffic jam on a hot day it will cycle between 85 and 95C on the gauge as the radiator fan cuts in and out.

Ducting around the rad to ensure all the air is funneled through seems to help more at high speed. On a motorway you can get overheating that ducting can solve. Plan to do this on my car. Had particular problems on French Autoroutes a few years back. Warm summer and 130kph led to problems. Had to knock the speed back about 10mph to keep the temperature under control.

Jen

[Man On The Clapham Omnibus]

Manifold wrap on the first two branches is necessary on mine in order to save the alternator from being barbecued. A small Japanese type of alternator will be farther from the heat and probably safe, but the old Lucas one is vulnerable to the radiant heat especially on idling after a few laps on track.

[Welly Jen]

I'll second that. Barbacued the Lucas alternator and replaced it with a tiny Japanese one, which can be angled further away from number 1 cylinder pipe.

[the stoat]

Check your fan, is it working? Is it spinning the right way? Is it moving enough air? FYI the size of the fan does not always relate to how much air it can shift.

 

I spent a huge amount of time sorting my cooling and if cooling at speed when the car is making more heat is fine you have a low speed air flow issue.  In short you are not getting enough through the radiator.

[Martyn Vann - Warwickshire AO]

With a good fan that is fitted the correct way round, a good radiator and all the air locks out a Pinto engined car can be fine for cooling. Mine has no exhaust wrap, no extra bonnet vents, no ducting around the radiator. It uses as a Polo radiator. In a traffic jam on a hot day it will cycle between 85 and 95C on the gauge as the radiator fan cuts in and out.

Jen

 

The cooling spec and performance of my 2.1 Pinto is the same as Jen's, no ducting or additional vents but I do have exhaust wrap.

 

I did have issues with air locks, which took some sorting, affecting high speed operation but slow speed overheating was down to a poor fan. Changing the old style down flow rad to the crossflow polo rad and a new fan cured all the issues, I also fitted an 82^oC thermostat. Like Jen I do plan to fit ducting for improvements for track day use. 

 

Is the fan switching on ok and at the correct temp, is the motor ok and turning fast enough and in the correct direction?

 

With regards to the exhaust wrap, it can reduce the under bonnet temps which does help protect the alternator and other items. It also can aid the exit of the exhaust gasses to optimise engine performance. Not had any issues or even heard of any problems when using it.

[Lawrie]

I don't think the water pump is efficient, so airlocks have to go.  Bleed the top hose

 

High under bonnet temperatures evaporate the fuel in the carbs too, usually once you've turned off.  There's a fair bit of venting through the wishbones

 

I found the Ford fan would blow the fuse.

[TREVORGIDLOW]

Thanks for the responses. Sounds like airlocks are the favourite...followed by fan and rad specs.

 

Crossflow Polo rad useful info. 

 

What would be a 'good fan' to combine with this?

[CosKev]

What fan is fitted now?

If it's a cheap electric one your better off going for a branded one like Spal.

Fit the biggest CFM one you can in the space you've got.

Ref fitting ducting,I used thin alloy sheet which I've bonded to my rad,this then sits nicely behind the lip on the nosecone.

[Man On The Clapham Omnibus]

Bleeding the Pinto is a problem because the expansion tank is lower than the highest point - or at least near enough on a level. You can unmount it and ask an assistant to hold it up while you bleed through the highest point. Usually there's a fan switch in the top hose but I released the hose clip at the high point and allowed it to bleed out through a crack at the top of the hose/spigot junction. It's not the odd bubble but a bulk of air that half fills the top hose which effectively reduces its carrying capacity. Instead of raising the expansion tank, I found a rubber tube that fitted well into the neck of the expansion tank and blew down it while releasing the air. The only time mine gets a bit hot now is either at sub-30mph extended periods or after a few hot laps on a track day as I approach the paddock and the ram effect is reduced. It never boils though - it did on the way home when I bought it and has never done so since I reversed the fan and bled the system.

[Martyn Vann - Warwickshire AO]

MOTCO is correct, I've always found lifting the header tank or applying pressure to the system whilst bleeding works well to expel air.

[Lyonspride]

Don't rely on the gauge to give any sort of accurate temp reading, they just don't. Mine over reads by a good 10c.

[bigron]

Another thread here suggests a good coolant can also help

http://forum.wscc.co.uk/forum/index.php/topic/118117-which-coolant-are-you-using/?fromsearch=1

[TREVORGIDLOW]

Don't rely on the gauge to give any sort of accurate temp reading, they just don't. Mine over reads by a good 10c.

 

Exactly what a trusted local mechanic who has worked on Pinto's racing at Brands Hatch has noted. He suggested taking a temperature of the rad itself, he said it more than likely that it's over reading the temp. He also noted that all the Pintos racing at Brands are running at 100C anyway because they're best run at this temp?