Mopar Muscle Association UK

hmm.

So, finally got me fitted with the big rad to replace my 22".
Its aa 26" 4-core monster rated to 800hp (overkill much? ) - fought me everystep of the way but now installed.

Heres the thing - I am not convinced its quite right.
Doesn't leak, blow over - coolant all nice and clear etc - Ran it for a good long run, high load, low load, left it idling for 30 mins - and there is something odd.

When car is running normally, it sits WAY down in the tempguage - almost like stat jammed open or something (brand new stat - but could be knacked I suppose). "A" in pic.
10 mins in town traffic and it might go up to "B".
30 mins idling on drive and it got to "C" (and things started smoking - but no boiling. Other things. So pretty hot.

Here's the thing - Good long drive today, sitting at "A" all the time, but when I got home the heat under the bonnet was really high - like felt way hotter than before. Temp guage cool, under-hood heat BIG. Timing checked - its rock solid at 17ish idle (and has not changed). Only thing I have changed is the rad and stat.

Air lock ? Water pump failure ? All the hoses get hot (like too hot to touch hot) :scratch:

Any ideas ? I have no 'proof' really - but it just don't feel right.

Got a 3 core in mine. Sits at 160-170 on a hot day when driving. Will run cooler when cold.
I've got a aftermarket Mech temp gauge in mine with capillary. Hits 185 and you can see it drop when it opens.

What kind of fan have you got?

Had it out this week. Stuck in traffic and it touched 190 at idle. Put some rpm by feathering and the temp dropped. Its a fixed fan.

I'm guessing at idle rpm the airflow via the fan is not drawing enough air through the rad and with not having moving air from forward motion its basically got a dead zone of air flow.

See if feathering shows an improvement?

If it does then its airflow.......I'd also expect that 30 mins of idle sat on your drive is not your normal weekend thing.....if its happy with driving temps then keep moving.

Other option for piece of mind would be get a temp gun!

You could test the stat in boiling water, I had one once brand new that would not open at all, even if you got it hotter than the sun.

Been through this myself . Fan looks close enough to rad to not require a spacer , shroud looks tight to rad. Driving temp fine , its when its stood on tickover..... Electric fan(s) as a pusher .??..if you can sit for 30 mins with standard fan that ain't bad on a big block but it depends on your comp ratio.
Al killer and I went the merc fan route with a controller. I believe Al killer is selling his on the forum for a bargain. There is a sticky on the forum I think and loads of on the US forums about this mega air draw solution. Just make sure your alternator is up to it.

Airlock in heater circuit? Jack front of car high as poss when filling system.

Try using and aftermarket temp gauge as the standard one are all over the place. Also this will give you a reference to see how good the standard one is.

I can see a 'bung' in the top of the water pump which looks like it would take a secondary gauge. Anyone happen to know what thread it is up there ? I think I will just put a second in.

Second gauge a good shout - get some actual measurements as to what is going on. Stat test easy enough too.

latil wrote:Airlock in heater circuit? Jack front of car high as poss when filling system.

I had to jack front of car up and run engine with rad cap off to get rid of airlock in heads, water level which was fine when filled when car level dropped a fair bit and needed topping up.

sometimes these high efficiency radiators only work at speed. the cores are too dence for low speeds.

had the same with a GT40, at anything below 70 mph it would run too hot. put the original radiator back in to cure the problem.

I have seen similar on Transmission coolers, Barry.

We found the fluid went through the Rad so quickly it did not lose any of its heat. Restrictors in place reduced the flow rate and improved the cooling effect.

Sounds strange but it worked.

Just a thought as this was a fault on mine.... Fine on open roads but in traffic loads of heat from engine itself & I checked everything until I found it..... Inside one of theexhaust manifold there is a flap diverts exhaust thru the head, thru the inlet manifold & out the other exhaust manifold when cold. It is meant to open during warm up but mine was heating the inlet all the time to the point the fuel in the carb was vapour ! I've jammed the flap in the open position & all runs cool & normal now ! Shaun

Just a thought as this was a fault on mine.... Fine on open roads but in traffic loads of heat from engine itself & I checked everything until I found it..... Inside one of theexhaust manifold there is a flap diverts exhaust thru the head, thru the inlet manifold & out the other exhaust manifold when cold. It is meant to open during warm up but mine was heating the inlet all the time to the point the fuel in the carb was vapour ! I've jammed the flap in the open position & all runs cool & normal now ! Shaun