Coolant fan kicking in more & old vs. new coolant
 

Since its been getting warmer out, I've noticed that my Paseo's radiator fan has been kicking in. Last year, even in the middle of summer, it didn't kick in as much as it has been thus far. I haven't changed anything on the car except for adding a warm air intake. That obviously will make it kick in more. I will try removing it now that its summer and see what happens. But it really isn't sucking THAT much warmer air, so I'm wondering if you guys have any other ideas.

This week I went to a lunch meeting with a coworker and he mentioned I should change the coolant since old coolant can loose its cooling ability. I've never heard of this, has anyone else?

You wrote that all is the same as last summer, except for a wai - are you sure you don't have some grill blocking still in there from winter? Of course that would make it run hotter. Coolant low? Silly question of course, but if you forgot to look...

I run a full grill block year round.

I'll have to check the coolant.

Old coolant loses its corrosion protection, but not so much its heat transfer properties. But your cooling system can degrade over time through buildup of scale in your water jacket and radiator, and radiator fin degradation.

If you go with the old, green antifreeze, it's recommended you change it every two years. With extended life antifreezes (yellow-green), you should change it every five years.

I'd throw in a bottle of Radiator Flush, then change the coolant.

I say check the fins, spend some under there with a small screwdriver or a fin rake. I was amazed at how many little rocks can get stuck in the fins and how many fins get bent over. Just my 2 cents...

While I'm sure I have bent fins and crud stuck in there. The grill block basically won't allow it to get worse since it blocks the entire radiator.

http://www.tercelreference.com/downloads/paseo013.jpg

Thanks for the pic Daox! I see what your saying now about the grill block, yeah don't worry about little rocks!

You could check to make sure there is not any air trapped in the cooling system. If the radiator cap isn't the highest point in the system there is usually a plug you can open to release any trapped air. Engine running of course!

Do you have a ScanGauge or other that shows the coolant temp? IMHO, analysis only by whether the fan comes on - or by watching a gauge needle - isn't very definitive.

You actually ran with full grill block last summer, driving the same type of roads and speeds and trip length that you are now? And rad fan didn't come on much last summer?

My car seems to need the grill blocking removed when the weather warms up, or the coolant temp will go up and the rad fan does come on. Are there actually drivers driving long runs or highway trips with full grill block in summer?

As I see it, with a full grill block, the only way to get an appreciable quantity of air through the radiator is to run the fan - unless you're running a/c with the temp slider somewhere in the middle, which will cause air to run through the heat exchanger - essentially the same as running it through the radiator.

Alright, I checked the coolant and it is not low. There is some in the reservoir plus the radiator is full.

Yup, I have a SG and an LED to monitor the rad fan coming on. It just seems to be heating up faster this year, and its not even full blown summer yet...

I do run the full grill block all summer long. I have a 21 mile commute to work. Most of it is 55 mph highway. The rad fan never turns on on the way to work in the cool morning. It used to come on 2-6 times depending on traffic on my way home. I have taken it on extended trips of 100+ miles. I avidly avoid the 65 mph highway as the fan cycles on quite a bit once its up to temp. At 55 it doesn't come on nearly as much. I'd say every 5-15 minutes. I'm also running with the alternator disabled in summer, so I don't care quite as much if the fan comes on a few times.