Zetec conversion, cooling seems marginal in traffic

[CAB]

Hello

Enquiring for a mate with a Zetec conversion.....

He has a new 2.0 L Zetec and and a new standard 1.8 K series sized radiator. The fan is fitted to the front of the rad and pushes air through. I'm going to check that the blades are on the correct way around for the direction of travel later.

In traffic the fan stays on and the temp creeps up to over 100 deg C (103-105-ish). Once on the move it cools down again, he has never been in traffic long enough for the fan to cut out but it seems to get a bit too hot. I have got him to jack the front of the car up and bleed the system, he got a lot of air out last night and about 0.5 L of additional coolant. Hopefully this will sort it out. Does anyone else have the same experience with the Zetec?

Regards

CAB

[Martin S.]

I have a '94 car with a 2ltr Zetec. Since I've modified it to produce more power it has been getting hot when standing with the fan coming on and not managing to always bring the temp down from 100, like your mates it's fine once moving. My fan is the type that pulls through the rad.

Spookily about 10 mins ago I just finished fitting a new CC "Ford" alloy rad with new fan switch. I've also fitted an 82deg stat instead of the standard 88deg one. I havn't taken it for a proper drive yet but stood on the drive the fan is now coming on just under an indicated 90 and and brings the temp down nicely. Time will tell if it'll be as good with the nose and bonnet on on a proper run.

 

Class 4 Zetec

[S47zz]

Just fit a bigger rad - it's a no brainer really 😳 😳

a bigger motor always needs a bigger rad 😬

[Jason Plato]

the std rad is good for 200bhp + .I'm using a std rad on my 226bhp Duratec.

 

What thermostat are you using ?

 

The std rad overcools the duratec on the move with the use of Raceline parts or for parts.

 

It culd be that the engine is coming up to the stat tempo and then overcooling ?

 

 

 

here is C7 TOP

Taffia rear gunner

 

[dannylt]

I don't understand how modifying the engine for more power causes it to generate appreciably more heat at stand still. Any engine at standstill will be making very little power. The time you need a bigger radiator is when your coolant temperature climbs when you're using lots of throttle?

[Martin S.]

I don't understand how modifying the engine for more power causes it to generate appreciably more heat at stand still.

.......I would have thought increasing the pressure in the cylinder (ie by getting the head skimmed to increase the CR) would make the temp within the cylinder increase even if you're not using the power (Charles/Boyles law ) ........although I did take my heater out at the same time which probably also had an effect. Anyway whatever the theory is, mine was getting too hot hence the change of rad (still a standard sized one) and stat. If I find it now overcools I'll put the 88deg stat back in.

 

From the reserch I did the only time you need a bigger rad is when you're racing and slipstreaming so not getting the airflow through the rad when on the power.

[dannylt]

At idle, you probably need less than a single horse power, so you can only have an issue if you have a blockage, stat or fan problem. Definitely not rad size! Cruising at 60 or so is still only about 10 to 20bhp.

 

You need a bigger rad when it can't reject enough heat even with good airflow. Race caterhams have a big front mounted fan to get enough air flow while slip streaming.

[CAB]

Thanks Gents

Jacked the front of the car up really high and bled the system again, added some more coolant and now the fan cuts out as well as in after about 30 seconds or so. Looks like it was an air lock in the system. I've been away for a few days so I don't know what it is like on the road with the nose cone and bonnet on, I'll let you know.

I had a look at the fan as well. The direction of rotation can be reversed as can the blades. It looks to me as if the blades could be on the wrong way around so it is not running as efficiently as it should.... He needs to check with the manufacturer to be sure. You can't take the fan off without cutting the lugs that are pushed through the rad so it's not that easy to see and he hasn't got any spares.

CAB