FC_fan

iTrader: (2)

86 na base/sport. standard, only mod racing beat header/pre-sil/2.5" to muffler.
so I changed my T-stat late last year and didn't drive the car from november to april this month. its been fine sitting at 1/4 up the temp gauge but I stopped to help a friend on road side and left car idling. when I got back in after 15 minutes, temp showed very close to 3/4 up gauge again. outside temp was probably 70 degrees F and I blasted the heater and started driving the speed limit (50mph) to see if it would cool down. it took a long time but it cooled down to maybe 3/8 up the gauge (normal was 1/4). under load it seemed to go up a tiny bit like going up an incline that wasn't very steep. cruising flat it seemed to stay the same.

so is that normal when the engine got that hot? previously due to my oil consumption, I think my oil rings are going but it still uses the same 1qt oil every 650-700 miles it has been since I figured it was rings. Or is it just the clutch on my fan? my fan has always spun really fast on startup for like 3 minutes and still does that. T-stat was replaced with stant but has 1/8 drilled hole on the housing where the jiggle pin would be on the mazda OEM. is it radiator cap, what? car has coolant and I always keep oil full, top it off a lot.

Landon303

iTrader: (25)

I'd be inclined to re-change that thermostat

j9fd3s

iTrader: (3)

and check the fan.

FC_fan

iTrader: (2)

last year I checked the fan and it seemed ok. it was getting warm at low speeds but when you sped up it was fine. so I changed the thermostat. I know that stant sucks but other people said that they drilled the hole and didn't have a problem. I can check it by putting in a pot of hot water right to see if it works? I haven't let it sit and idle much this year, just at startup until it registers on the gauge or higher on cold days. its been cold up here (40's) so that was the first hot day. I'm inclined to think its the fan clutch if it did it idling. I figured that driving it at 50mph would cool it right down but it took quite a while and heat was full on too so that worries me. I didn't notice if my fan was on when it was that hot idling. it should have been right? guess I should get a mazda t stat anyway. thanks

FC_fan

iTrader: (2)

someday, I'm planning on doing a t2 swap (still need my rebuild kit, and money 4years later lol). think its worth it to wire in a taurus fan (electric fan setup, as I obviously have clutch) now rather then later? I'm planning on v mount sso it would require an electric anyway. might as well is what I think.

texFCturboII

iTrader: (17)

stock clutch fan > electric fan

That's just an opinion, and a highly contested one. IMHO, the clutch fan works great, it's simple and reliable with no worrying about improper wiring or overloading the old electrics.

How are you checking the fan, anyways? The procedure is easy: when cold it should be hard to turn; when warm it should spin easily.

clokker

iTrader: (2)

Contested, indeed.
Too bad a new thermoclutch costs a bazzilion dollars.

It's be easier if you defined "hard to turn" and "spin easily".

texFCturboII

iTrader: (17)

That's a good point. When cold, if you spin the fan it should make a few revolutions and come to a stop. When at op. temperature it should spin for a while, with less force required to spin it.

texFCturboII

iTrader: (17)

Sure, but there are used ones aplenty, for cheap. Btw, I think a great junkyard dig would be for a compatible clutch-fan off another model... If I ever get into this alltrac project of mine I may look for one soon.

misterstyx69

iTrader: (142)

do you have the plastic undertray on the car?

FC_fan

iTrader: (2)

ok. I tested the clutch fan last year as per fsm. cold start, hot start blah blah. did it the right way, should have mentioned that. but maybe its finally on its way out. could it be anything else at idle other then the fan?

I'm a fan of the clutch fan too but like clokker said, they are expensive and a used one is well, very old and used just like mine. So I'm not sure which way to go on it. I know people have converted to taurus fans and been fine electrically speaking. if I need to I could just run higher gauge cable and redo some of the battery wiring or give it its own, etc another thread story...

I have the aluminum under tray in place and fan shroud. its all stock with no components missing. I'm wondering if maybe I have an air pocket in my cooling system too. I'm gonna bleed that again and see. I will check the fan again and report back. I have my auto class tonight so maybe I'll get a chance to check it there. thanks for all the help and info. I don't have a high post count but have been reading on here for years about various issues and have decent mechanical ability.

FC_fan

iTrader: (2)

well, the fan spins a turn or 2 cold and stops so it has resistance. but after driving it at operating temp and shutting the car off, the fan has the same resistance. it is same as when cold, it doesn't spin freely at all. so that must be the culprit? another thing, my o2 sensor has not been connected but I just finally broke loose the broken one in my header so will be remedied soon. would that make a difference at idle do you think?

Rob XX 7

iTrader: (8)

It could be the waterpump corroded or the bearing is bad. I had this. Car would idle warm and once it got good airflow the temps would drop. Pump by itself without the airflow was not sufficient

jjwalker

With a properly working cooling system, you shouldn't actually hit operating temp at idle. On my S5, If i start it cold and just let it idle to operating temp, It will register about half a needle width below its normal operating temp location. Before anyone asks...

1)Aftermarket copper radiator, nothing special.
2) new, nothing special, mazda OEM T-stat with jiggly pin
3) simple, OEM clutch fan
4) 50/50 coolant, again, nothing special.

clokker

iTrader: (2)

I would assert just the opposite:
A properly working cooling system will always heat up to operating temp and maintain temp within an acceptable range. That's the whole point of thermostat.

Even an engine at idle will sooner or later heat up past the opening temp of the thermostat.

I'd suggest that your particular results are clouded by two things...the "always ON" nature of the mechanical fan and the extremely non-linear nature of the S5 temp "gauge".
The FSM gives the acceptable margin of error for the gauge as one needle width, so "1/2 needle" difference is below the granularity of the gauge, it's not that accurate.

texFCturboII

iTrader: (17)

Yes.

FC_fan

iTrader: (2)

I'm gonna check the water pump too. would it be weeping at all or just not doing a very good job. drove it the 42 miles to work and back today with no problems. I go up a steep grade up a mountain on my way home (5th at 2400 rpms can get me up without it floored) and as soon as I hit that grade the temp jumped up about 1/8th so up to 3/8th. when it leveled out it was back down to the normal 1/4th. so waterpump may be something too as I was going the same speed as before but load changed and fan should not need to come on at 50-55 mph. as long as its under a half I'm not worried but would like it pin pointed.

I saw something real quick about refilling the silicone in the clutch fan to fix it(might be 1st gen, can't recall). anyone know anything about this? I'm gonna search right now but figured I'd ask.

clokker

iTrader: (2)

Tomorrow try going up the hill in fourth.

FC_fan

iTrader: (2)

^I know where you're going with this. I admit that I'm not the know all guru mechanic of all time but I am competent. I usually do go up there in 4th. I did it in 5th for a control element as 5th is my cruising gear at that speed and going up that hill at 2500 rpms was possible and not bogging at all, just more load. the temp jump up the hill might be normal as the engine has more load on it but I can't help but think that if the cooling system was doing its job then it should not move that amount on the gauge. the s4 gauge is far more accurate then the s5 so maybe that comes into the equation.

On the other hand, what if I was tracking the car? it would see even more heat from high rpms and more all around load on the engine. so my temp would go up a lot then. I just need to figure out which part is going and it seems to me that its less the fan (but still might need replacing as well), more the waterpump, radiator cap, or coolant seals in the block possibly.

since I have no history on the car other then a blank car fax that says it resided in maine most its life and nothing else, I'm just going to replace the water pump and radiator cap. if anything, it will fix some up coming problems for me. car just rolled over to 160k miles so its at that point in its life. seems like over the last few thousand miles everything is breaking. wiper linkage, wiper switch, signal switch arm, cigerette lighter power, heater temp control arm for the flap, etc, etc. it's far from mint but does it really have to just fall apart all at the same time? lol

Hecubus84

iTrader: (1)

Are you using the stock temp gauge? That thing is so inaccurate that it may as well be a idiot light telling you to replace your engine. Try installing a aftermarket gauge before you start chasing your tail on a problem you may not even have.

FC_fan

iTrader: (2)

well I have an s4, which everyone says has a very accurate temp gauge. The s5 is the horrible one. Mine seems to work fine. it goes up to operating temp and mostly stays there. I left it idling 15 minutes and it ran up to 3/4. cooled down while driving a lot but not completely. seems to me its probably working fine. I'll test the sending unit just in case I suppose.

either way, water pump and radiator cap would be good to do at this point in the cars life. and getting a mazda oem t stat. then if that does nothing and that sending unit is good, the fan will be replaced. thank you all for the info and advice.

clokker

iTrader: (2)

Hell, I'm not even sure where that was going.

Why has the radiator not entered this conversation?
Stock rad, AC?

FC_fan

iTrader: (2)

stock radiator, no AC pump at all. checked for cold spots and hot spots and radiator feels normal. both radiator hoses are the temps they should be. I am leaving radiator for last because if it was the radiator, wouldn't it want to overheat all the time? it just starts to get hot at idle, driving is mostly fine other then me thinking that it should not go up 1/8 when I put the engine under load sometimes. Of course, it could always be my stant t stat crapped out. I guess I should get oem just in case.

first I want to get a new radiator cap. I tested the sender for the temp gauge and its fine. what would be your best guess clokker, water pump or fan? or radiator I guess but let me know the symptoms of the radiator issue because maybe I'm missing something?

clutch fan (just the clutch) at rockauto is 120usd. water pump is 39usd with the gasket. not too bad.

also, would the fan engage when driving 50mph on a hot day? I assumed not but maybe I'm mistaken. I didn't think it should need to so thats why I was thinking on that water pump idea.

FC_fan

iTrader: (2)

I take it back, rad cap, then BELTS! then the expensive stuff. my belts look worn a little bit. I'm going to see if replacing those helps out along with the rad cap and go from there. thanks again guys.

clokker

iTrader: (2)

The troubling thing isn't that the temp spikes up- the system is always in flux- the issue is that it takes so long to recover.
I'd replace the thermostat, rad cap and waterpump at the same time, see if the scorched earth approach works. Saves on coolant, at least.