Overheating

Trance101 · Post by **Trance101** » Thu Feb 07, 2008 12:21 pm

Hey guys,

My sx's aircon had no tensioner pulley when I bought the car so I managed to buy the pulley from Gary. I have now attached the pulley and installed a new belt.

The aircon worked fine after that, however, I did a longish highway drive the other day and my sx overheated

Any idea if this would have summing to do with the aircon now working? It was a blisteringly hot day here but that shouldn't matter, the cooling system should be able to take it. The temperature gauge got very close to the red and water was boiling in the watter bottle by the time I was able to stop... on the way home it got hotter than usual so I switched the aircon off but it still remained quite hot (like 3 quarters of the gauge) until I got home.

The radiator was full, there are no water leaks that I can find, the water pump seems to be working (can see water flowing through the radiator)... so any idea what may b the problem? I only have one 12" electric fan on the radiator is that not enough? I hear 2 x 10" fans are a better option, should I look at replacing my fan?

Gary57 · Post by **Gary57** » Thu Feb 07, 2008 12:35 pm

I would think the fan would be the best bet.

n1smo200sx · Post by **n1smo200sx** » Thu Feb 07, 2008 12:51 pm

The ONLY way to keep the car from overheating is to put the original fan back.Else you going to spend a lot of money on a huge radiator ans also one fan isnt nearly enough when running the aircon.Thats prob why the aircon wasnt connected in the first place.

Trance101 · Post by **Trance101** » Thu Feb 07, 2008 1:50 pm

Ok, thanks guys. It sounds like the fan is the problem.

I don't have the original fan so I can't put that back, so what combination of fans do you think would be the next best bet? 2 x 10"?

What are the guys that are using electric fans running?

Gary57 · Post by **Gary57** » Thu Feb 07, 2008 2:12 pm

Is the car still overheating now, even on a average day??

Trance101 · Post by **Trance101** » Thu Feb 07, 2008 2:21 pm

Gary57 wrote:Is the car still overheating now, even on a average day??

I haven't driven a long enough distance since it overheated (Tues) to find out. I'l take a good long drive this afternoon and find out. Today isn't as hot as Tuesday was so it will be a good test.

Speed breeder · Post by **Speed breeder** » Thu Feb 07, 2008 2:22 pm

Can the mechanical fan really be a better cooling mechanism than an electric fan?

At low RPM's your mechanical fan turns at low RPM's, whilst an electric fan has the same PRM's throughout the rev range.

I would imagine 2x10" would be better to cover a larger area of the radiator, whilst a 12" may not cover left and right.

Maybe also check other things, like head gasket.

Keep an eye on the water pump, as they tend to start leaking when the car got too hot.

I am not a mechanic, this is what I have experienced.

Had to replace water pump twice so far. Using electric fan though.

Also check if your electric fan comes on at all and when it should.

Trance101 · Post by **Trance101** » Thu Feb 07, 2008 3:55 pm

Ok, will check those things, thanks. My electric fan is always on though, as long as the car i on the fan is on.

I went for a drive now, and had the aircon on full. Within about 10km of semi hard driving the temp started to rise above normal. I switched the aircon off and it returned to normal after some careful driving. I then switched it on again and drove normally and it went up again.

I then drove hard again with aircon off and after about another 15km the temp went up as well. I think my fan is to weak.

I'd like to get two new good electric fans, does anyone have any recommendations for me?

Draco · Post by **Draco** » Thu Feb 07, 2008 4:05 pm

Except for the thing mentioned....look at your thermostat aswell and then when you put in electric fans you need to install a heat temp swich connected to a relay to switch the fans on and off, obviosly the cooler temp switch you take the sooner the fans will go on....

Hotstuff · Post by **Hotstuff** » Thu Feb 07, 2008 4:17 pm

Correct there Draco,

I have 2 x 10" electric fans fitted and they run off a switch and relay setup which works damn well. The temp switch is located at the bottom hose of the radiator and sends signals to the power source and relays to activatre the fans once a certain temp is reached.

My car runs cool, even in peak hour bumper to bumper traffic. I spent 2 hours in traffic to get home one day and the gauge didn't even venture pass the halfway mark at any stage.

Gary57 · Post by **Gary57** » Thu Feb 07, 2008 4:20 pm

Is the tempreture only rising recently or has it always been like that??

veecee · Post by **veecee** » Thu Feb 07, 2008 5:12 pm

there is only one reason related to the aircon that will affect this. the fact that the aircon radiator blocks airflow through your radiator.

but this is from the factory so it actually doesnt make a difference.

your problem according to the information you've supplied seems to me to be twofold.

1. you have no temperature switch activating the fan. like draco says, you need to install a temp switch, connect it to a relay, and connect the relay to your fan(s).

2. you only have 1 x 12" fan. this isn't wise at all. 2 x 10" would be better than this... BUT... 2 x 12" is your best bet. i have 2 12" electric fans installed and i never have overheating problems, but then again, my motor is quite stock. they fit onto that huge radiator perfectly.

just go buy another 12" fan and you're sorted. then buy a temp switch, i'm using one from a e30 BMW 325i because it has 2 switches built into it. one fan comes on at a low temp, and if the temp raises then the other fan turns on. dont forget to get yourself a relay too.

oh ja - lastly - make sure your fans are flush mounted to the radiator. if they can suck in air from anywhere else except through the radiator, then you will have problems too!

Toby · Post by **Toby** » Thu Feb 07, 2008 5:59 pm

The reason why the stock viscous fan is so effective is because of that massive and all-encompassing shroud! It makes sure that almost all the air extracted comes through the radiators. Don't under-estimate the importance of the shroud.

veecee · Post by **veecee** » Thu Feb 07, 2008 8:03 pm

yup - exactly why i mentioned that if you are going to use the electric fans, make sure they are mounted flush against radiator core!

i've seen a number of cars (including masturbated ones) that had a stupid heavy steel frame built to hold the fans to the radiator. this leaves them at least 3-4mm away from the radiator, and it results in the fans not blowing or sucking air through the radiator fins. instead it escapes through those side holes!

Ero_sennin · Post by **Ero_sennin** » Thu Feb 07, 2008 8:32 pm

veecee wrote:yup - exactly why i mentioned that if you are going to use the electric fans, make sure they are mounted flush against radiator core!

i've seen a number of cars (including masturbated ones) that had a stupid heavy steel frame built to hold the fans to the radiator. this leaves them at least 3-4mm away from the radiator, and it results in the fans not blowing or sucking air through the radiator fins. instead it escapes through those side holes!

well he had mine fitted against the radiator, altho it was a radiator built by a radiator guy, and he built it so that the fans fit perfectly against the radiator.