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I am wondering if there are any guys out there who do any road racing with their KL swaps and if they have run into any over heating issues...

Today was the first day I have run on road race track.. After about 2 - 3 laps I would start to over heat.. Once that was hot I had to run the rest of the 20 min session at only half throttle and short shifting.... I have never had any problems at autocross racing, drag racing or on the streets... I rarely have to use the cooling fan on the streets unless I am in a lot of stop and go traffic..

The car is a 323 with a stock front bumper on it.... Its a 93 KLDE unkown miles, no internal mods and not much for bolt ons... Stock computer.. it runs a 91 - 94 cavalier 2.2L rad...The rad was bought brand new when the car was put together.. When the car was put together the motor got a brand new timing belt, water pump, 180 deg thermostat and all new coolant lines

It seems I am only over heating when I am running at full throttle and sustained high rpms for longer periods of time..

any idea?

Are you running a single rad. fan? I don't know overly much about this, but it certainly wouldn't hurt to do a dual fan setup, 1 pushing and 1 pulling.

Ran fans only kick in when you're not moving enough air, typically at idle/stopped. Rans should never be running when at speed, there should be plenty of air pushing across the rad to cool it. Having a pushing fan will not work since it'll be pushing against air that's coming in at high-speeds, probably just creating a deadspot right at the rad, making things worse.

Unfortunately I've never road raced, but I've driven hard for long periods of time back in the day that would put the engine at work harder than at a track.

I've never had problems with overheating except with my rad fan not wanting to kick in, always liked to do that in traffic...

Actually I don't have much idea on what it could be. It doesn't make sense if that's the only time you have that issue.

I'm wondering why you're running a 4cyl rad from a Cavalier. That's the only thing that strikes me as odd.

You're having several problems here.

First, road racing is probably the most demanding form of racing, on the car as a whole, and especially on the engine and tranny. Not only you run most of the race at high revs (which, of course, generates a lot of heat), but you're racing, most of the times, at speeds that aren't that high, so you don't have a lot of airflow through the radiator.

Second, stock radiators are not calculated for that kind of sustained high rev driving. Even if you used a KL radiator, chances are your engine would still overheat.

Third, you're actually using a radiator for a SMALLER engine than yours, which even in normal driving generates less heat than the KL.

Because of all that, it's not surprising at all that your engine is overheating. You should use a radiator for a BIGGER engine, not a smaller one. If I were you, I'd start with a Ford 3.8L radiator, and see how it goes. Also, it wouldn't be a bad idea to cut a couple of vents on the hood, to help get the hot air out of the engine bay. Using a push-pull setup, as MM92 suggested, can also help.

Nd4SpdSe wrote: Having a pushing fan will not work since it'll be pushing against air that's coming in at high-speeds, probably just creating a deadspot right at the rad, making things worse.

Pushing fans are mounted IN FRONT of the radiator, pushing the incoming air towards the pulling fan, to maximize it's efficiency, not against the airflow.

Inodoro Pereyra wrote:Even if you used a KL radiator, chances are your engine would still overheat.

A stock Mx-3 rad on a KLZE Mx-3 should have no problem keeping up road racing. There's MANY Mx3'ers that road race. Look at specifically the MOCA guys. I never heard of road racing causing known overheating problems, and they're more from down south with hotter temperatures.

Inodoro Pereyra wrote:Pushing fans are mounted IN FRONT of the radiator, pushing the incoming air towards the pulling fan, to maximize it's efficiency, not against the airflow.

They don't have to, depends on the fans and the setup. Is there even room in front of the rad for a front-mounted pushing setup? I recall not really. Also the problem with a pushing fan is the turbulance caused from the air being pushed, it's not an efficient way to extract heat of off a radiator in that manner.

2 FAL fans pulling (higher CFU rating with lower draw) and buy a crysis Co2 kit for when temps really start to peak.

Nd4SpdSe wrote:

Inodoro Pereyra wrote:Even if you used a KL radiator, chances are your engine would still overheat.

A stock Mx-3 rad on a KLZE Mx-3 should have no problem keeping up road racing. There's MANY Mx3'ers that road race. Look at specifically the MOCA guys. I never heard of road racing causing known overheating problems, and they're more from down south with hotter temperatures.

So what are you suggesting? That he replaces the radiator from a 2.2 L engine, that's making his engine overheat, for the radiator from a 1.8 L?
Sure, I can see how that makes perfect sense. In YOUR World.

Nd4SpdSe wrote:

Inodoro Pereyra wrote:Pushing fans are mounted IN FRONT of the radiator, pushing the incoming air towards the pulling fan, to maximize it's efficiency, not against the airflow.

They don't have to, depends on the fans and the setup. Is there even room in front of the rad for a front-mounted pushing setup? I recall not really. Also the problem with a pushing fan is the turbulance caused from the air being pushed, it's not an efficient way to extract heat of off a radiator in that manner.

So, basically what you're saying is you messed up, and you aren't man enough to accept it. Got it.
Pushing fans are ALWAYS mounted in front of the radiator, regardless of the fans or the setup. You'd have to be VERY DUMB to even think about installing a fan pushing air against the incoming airflow.
Pushing fans are NEVER installed alone, unless you have a turbo or any other piece of equipment taking the room of the regular, pulling fan. Pushing fans are installed in a push-pull setup, to increase the efficiency of the pulling fan, and therefore increase cooling.
There's nothing left to discuss here. There's no mystery involved. Push-pull setups have been used for decades, and are still very popular, because they DO INCREASE COOLING, regardless of any excuse you'd want to make about them.

Alright kids, let's not turn this into a d----measuring contest like always. God this forum is falling apart, I don't even comment on most of the stuff anymore cause I know there's gonna be some jacka** who can't put his ego aside.

My friend who origonally started building the car used a cavalier rad as that what he found fit the best in the front of the car at the time he was building it.. The 323's are a little more cramped up front when doing the KL swaps then Mx3's....

Anyone know the direction of flow for the cooling system?

What rad set ups are people running?

@Inodoro Pereyra

I believe what Night shade is pointing out is that the radiator from a cavalier is a smaller surface area resulting in poor cooling. Displacement has nothing to due with how efficient an engines cooling passages are and the mass of the engine trying to be maintained. For that matter look at your older gm trucks, they came with 350 v8s that had a variety of cooler options based on what packages you needed, such as towing, daily driver or work truck.

Secondly as for the matter of a pushing fan, I agree with Nd4SpdSe that if your vehicle is underway they do more to impeed air flow on a properly ducted setup. HOWEVER, when sitting at a standstill with no incoming air directed over the cooling system I would say they would be ideal. Such as pit time or waiting between runs.

@ crazycanadian

My personal approach to this would be to source an aftermarket radiator for a cavalier as you already have mounting mocked up and there is a wide range of support for them. Ideally I would go with a dual core setup or have one built for you http://www.griffinrad.com/compact_car.cfm

First though would be to make sure you have adaquate ducting, it makes a huge difference. Make sure the air is routed where you want it and make sure your fans are covering the whole surface of the rad if possible. Also swap out for a lower temp thermostat and put the front wheels in the air and bleed the system for any possible trapped air, occasionaly air pockets can get stuck back by the heater core/hot water valve.

Second I would invest in some quality fans, mainly pull fans you could wire into your temp sensor, again I like the Flexlite FAL fans because of the greater CFUs. Then if you do alot of idling time maybe a pull on a toggle switch for that extra help.

And if you want a lil extra help a Co2 spray kit and some water wetter product would also aid you quite a bit.

Hope this helps, its just what I would do.

Otherwise if anyone disagrees with me feel free to pm, otherwise lets just offer pointers and I'll modify my post if necessairy

crazycanadian wrote:My friend who origonally started building the car used a cavalier rad as that what he found fit the best in the front of the car at the time he was building it.. The 323's are a little more cramped up front when doing the KL swaps then Mx3's....

I imagined it'd be something like that.
That would've worked ok, for a street application, but when you're running at over 5K, 80% of the time, you're bound to have problems. Also, I don't know what category of racing you're doing, but I'm fairly sure they won't allow you to use coolant, or any additive on the track, just straight water, which helps compound the problem.
The way I see it, you don't have a lot of choices here. Either you modify the front of the car to fit a bigger radiator, you install a push-pull fan setup, or you look for an aftermarket radiator (and be ready to pay for it), that can provide you the extra cooling you need.
I would personally modify the radiator support, to fit a bigger one, and fit the push pull fan setup for some extra peace of mind.
Also, if you have an A/C system in your car, you could get rid of it, especially the condenser (it sits in front of the radiator, passenger side). That should also make a big difference, maybe even enough that you don't have to modify anything else.

crazycanadian wrote:Anyone know the direction of flow for the cooling system?

It's the same in all engines. The cool water enters the engine through the lower hose, directly to the water pump, and exits the engine on top, at the thermostat.

Sleeper thanks for the input... As for Rad if I am going to change it out I'll go to something completely different... I don't have the bank roll to buy anything new or have it custom built...As for bleeding the air out of the system I do things one better with vacuum bleeding the system free of air... The thermostat is all ready a new lower temp thermostat...

There are some differences in size between the 2.2L cavalier rad the the stock rad... The 2.2L is smaller but the core is thicker..

I am really curious which side is the inlet and which side is the outlet on the rad and the direction of coolant flow threw the rad... I think I might have a flow problem as the 2.2L rad has different inlet and out lets... On the drivers side the 2.5L rad inlet/outlet would be at the bottom of the rad.. On the 2.2L rad its at the top... On the passenger side the 2.5L rad would be at the top of the rad where as the 2.2L rad is at the bottom... I think this causing problems with how the coolant is flowing threw the rad and threw the motor..

Ducting is something I was looking at while at the track... I am all ready looking at mocking up a air duct system ...

As for rad fans I could switch out to a flex a light fan but I can only cover about 1/2 to a little more then half of the rad with a fan... I have 0 room in front of the headers to put a pull fan in... The fan I have in there now does a good job at cooling the car down.. When the car has gotten hot and I turn the fan on it brings the temps down quickly...

Inodoro Pereyra wrote:

crazycanadian wrote:Anyone know the direction of flow for the cooling system?

It's the same in all engines. The cool water enters the engine through the lower hose, directly to the water pump, and exits the engine on top, at the thermostat.

Not all engines are the same some are reverse flow... The 2.5L rad has the thermostat side running to the bottom of the rad and the water pump side running to the top of the rad... I am curious about this because my cavalier rad is set up the opposite...


The primary racing I do is autocross... I haven't had any problems with this though... This was the first time I got the chance to do a lapping day at the local road race track... I don't plan on doing road racing with the car it'd just be nice to see if I can get it to stay cool so I can go out to a few more lapping days and get to run the car full out...

crazycanadian wrote: I am really curious which side is the inlet and which side is the outlet on the rad and the direction of coolant flow threw the rad... I think I might have a flow problem as the 2.2L rad has different inlet and out lets... On the drivers side the 2.5L rad inlet/outlet would be at the bottom of the rad.. On the 2.2L rad its at the top... On the passenger side the 2.5L rad would be at the top of the rad where as the 2.2L rad is at the bottom... I think this causing problems with how the coolant is flowing threw the rad and threw the motor..

The coolant should enter the radiator at the top, straight from the thermostat, and exit at the bottom. If you have it backwards, it will generate a little backpressure, that could hinder its efficiency a bit, as the flow has to fight gravity (and convection) to go through. Maybe all you need is to swap out the hoses, and the increase in efficiency might be enough to keep your temperature under control...

crazycanadian wrote:As for rad fans I could switch out to a flex a light fan but I can only cover about 1/2 to a little more then half of the rad with a fan... I have 0 room in front of the headers to put a pull fan in... The fan I have in there now does a good job at cooling the car down.. When the car has gotten hot and I turn the fan on it brings the temps down quickly...

That brings another potential source of trouble. Are your headers shielded?
If your front header is sitting close to the radiator, it's heating it up. You can either put a shield between the header and the radiator, or you can wrap your headers with exhaust tape. That could also decrease your coolant temperature significantly.

crazycanadian wrote: Not all engines are the same some are reverse flow... The 2.5L rad has the thermostat side running to the bottom of the rad and the water pump side running to the top of the rad...

No, it doesn't. I had an MX-6, bone stock, with a KL-DE. The top hose goes to the thermostat (driver's side), and the bottom hose goes to the water pump.

Reverse flow doesn't make any sense in a cooling system. You want the hot water to enter the radiator at the top, so, while it gets cooler, its own density increase helps it flow to the bottom. Doing it the other way around would be to waste resources.