Checking if radiator fan is operating correctly.

[mo_ayman]

I am having an overheating issue lately.

Everything is looking good. I can't spot something wrong.

Considering that the issue happens only when am at a stop, I am starting to suspect that it is the fan. It though works as the dash shows 90+ ° C.

I guess though that it has 2 speeds. I don't know how to test such thing though. Is there a way to force the faster speed?

How can I male sure that my fan is 100%.

[Cavalier342]

Hi, what engine/spec is your car? The V6 models have 2 speeds on the radiator fan, as far as I know the other models have a single speed, can you hear the fan activate while you are driving? It's loud enough to be heard if you don't have extremely loud metal blasting out through the stereo.

Depending on the engine spec, radiator fan should come on at around 95-100C on the dash temperature gauge, if the gauge is reading accurate that is, have you tried keeping a steady amount of revs while parked to bring the temperature up to hear the fan kick in?

[mo_ayman]

Sorry for not mentioning my spec.

I have the 1.6 SOHC. It is a 1995.

Although, blasting metal through the speakers, I am certain that the fan turns on as I drive.

I have also made sure that it works while stationary by getting the car up to temp.

I am also sure that the water circulates through the system and what I have done was open the cap of the coolant overflow and witnessing the return coming from the radiator.

Since I had my car the normal operating temp was 90-93 or so and with AC on it goes to 96 right above the 95 mark and stays there no matter what. I have never seen the temp go more than 96, it once happened when the radiator fan cable broke off and it caused the radiator side to blow off so I replaced both the radiator and fan that was 2 years ago.

The overheating issue started since last week. I have seen the temp rise all the way up to 100 which was alarming to me that was with the AC on when I turned it off the temp went back to 96 after a bit.

I though believe that the radiator fan used to have two speeds.

[mo_ayman]

Another tiny piece of info, my dash has the temp gauge having the last mark as 100°c and not 110°c.

I have seen dashes with 110°c I don't know but I believe those are ones for bigger engines than mine.

[Cavalier342]

Hmm, a 1.6 with air con, now that's a rare one! Generally speaking most petrol engine models operate once warmed up at anywhere between 92 to 95-96 roughly speaking on the gauge. Anything hotter and the fan should kick in.

If you have air-con, then you may have either a twin speed setting or an extra fan, I'm not experienced with air con stuff, but someone here will tell you for definite.

Just wondering if you have tested for air locks in the coolant system, to do that, you leave the expansion tank cap off, run the engine until it warms up, and when it gets warm, gently sqeeeze the big hoses, one either side of the radiator, if you see bubbles come up in the expansion tank, then there is some air in the system. Do that a few times until bubbles don't come up, then close the cap tight.

[mo_ayman]

There is a separate small fan for the AC. The radiator however has only one fan. I have bought the car with AC since 1995 I don't know why is that surprising to most of the people here. You aren't the first one who says so.

I will try to check for air pockets in the cooling system and will let you know how things go.

[Cavalier342]

It's just that those sort of models don't come up very often at all in topics, most Cavaliers on the road now are 1.8's or 2.0, 8v and 16v, plus the odd V6s and rare early models, but a 1.6 with air con from that last year of manufacture is extremely rare, others will confirm this.

Keep us posted on how things go.

[James McGrath]

Is yours a Vauxhall or an Opel?
As far as I know 1.6 Cavaliers were never officially offered for sale with Air con.
Air con was standard on all Diplomats, was an option on all Turbos and an option on the 1992 model year GSi.
Right at the very end (1995 model year) air con was offered as an extra on all cavaliers equipped with either the X20XEV (2.0i ecotech) or C25XE (2.5i V6) engines. So that includes all models such as LS, GLS, SRi and CDX.
If yours is a Vauxhall then you have a very rare car indeed. I can only imagine that it was specially requested by either someone with influence or by a company.


Anyway, a way to test to see if the fan is working is to unplug the wiring connector on the fan temperature switch (should be screwed into the bottom of the radiator on the drivers side) and short the two pins while the engine is on. The fan should just kick right in.

If the engine isn't going above 96 degrees though, it sounds as if it's working and you have nothing to worry about.

[mo_ayman]

Well yeah I guess you got it right.

It is an Opel Vectra A. Maybe that's why. I thought Vauxhall Cavalier MK3 and Opel Vectra A are identical.

Unfortunately, the temp goes all the way up to 100. The fan works. I want to test the 2 speeds of the fan.

Umm, anyway I won't be able to reply soon because I am out of town. I will update you guys ASAP. Thanks.

[mo_ayman]

So, I have checked for air pockets in the system and everything was fine, none were found.

I made sure that the fan works on both speeds!

So, I ended up going to a opel mechanic. What he did was remove the thermostat spring, keeping it open all the time. Although I didn't want to do this and do think that it may be harmful, I let him do it.
He said that most people remove the thermostat spring because we are in a hot country and the engine is never cool even in winter when temp is 15c or so.

Testing a little bit. I found that the car still overheats. I am puzzled and don't know what to do.

Umm, I will list the things that are not OEM in my car.
- The radiator fan
- The radiator
- The exhaust mid section and rear section (can this be it)?

Recent stuff I have done was:
- Change the cooling from normal water to (Mobil Coolant ready mixed 33% green one)
- Change the engine oil from Mobil super XHP 20W50 (low milage thicker oil) to Mobil 1 0w20 full synthetic

What should I do? I am thinking about getting rid of my car now. It is getting pretty tiring :/ .

[mo_ayman]

So umm,

It ended up being a clogged radiator.

In my very last reply, I mentioned that I recently flushed the cooling system and went from normal water to green coolant. I have used water for more than a year.

My theory is, flushing the system before using the green coolant moved the rust around which was accumulated over time from using water to the radiator blocking some of its channels causing the overheating issue.

I am curious though how does the radiator look like from the inside and how badly clogged it is. I have the old one right here but didn't decide to open its plastic sides to check it. *halo*

Now the car is perfect and running like new since I changed the radiator.

Lesson learned, I will never use water again and if I had to I will use distilled water. I have no idea how it started, me using water and not coolant.

Thanks for anyone who tried to help.

[Mk3alan]

As you found out, just water not good!
I fitted a new quality rad and cut open my 20 year old Astra radiator as I was concerned about possible corrosion to the autobox oil cooler - a big unknown with expensive consequences if it did leak.
Coolant always maintained a good colour and the interior of the old rad was spotless, obviously the coolant had been maintained correctly.

Alan

[iangsi]

By Green coolant I take it you mean the waterless coolant that's available nowadays, not used it myself but I've heard you need to thoroughly flush & dry the cooling system for it to work properly.

[Robsey]

For as long as memory serves, I have always used the red / orange long life coolant at the recommended mixture ratio.

Replaced with fresh every 12 months.

Flushing of any car of the standard Cavalier age will indeed dislodge many years worth of crud.

I would never use water only...
I have a relative who did this for a month or so due to a persistant coolant leak.
Problem is, he chose to do it in the depths of winter, and was rewarded with a cracked engine block when the plain water froze solid.
Result - scrapped car due to cost of a replacement engine.

There in lies the lesson. !!

I have never tried waterless...
So cannot comment on the merits or drawbacks of using it.