WonkoTheSane

iTrader: (2)

Alright, I recieved a lot of good comments and things in my last thread about this (no real relevance, to now, though), and that lead me to where I am tonight...

Here's the deal, sparky:

I just got done installing my new water pump tonight, two weeks ago I swapped my radiator to a known good one, and all my hoses are new. My thermostat is a Mazda OEM one, about one month old. I'm going outside to remove it right now to see how it does tomorrow. There is no coolant places to leak or anything on the rear of the block, as ALL BAC valves and such are removed. Nothing there, nothing to go wrong, right?

The engine has 6000 miles on it from my rebuild. It only lightly smokes on startup, but that's defiantly oil or something burning, and once I get a chance to rev it a bit, it goes away. I just changed the oil about 400 miles ago, and there was NO liquids in the oil, although my oil level was down quite a bit. I think that may be attributed tot he fact that my MOP is stuck open most of the time. So as far as I can determine, it's not a blown coolant seal.

I JUST got back from a bit of a canyon run. The total run lenght: ~12-14 miles.

For the run UP the mountain, I ran the car really hard. I would redline every gear, get up to high speed, slow down, get back to speed, etc. (top speed was probably nearly 105 (briefly) on some straights)

My temp gauge never showed above 1/4th. HA! I thought,, my overheating problems are gone, my new waterpump fixed it! Not so.

I got to the top and slowed down to turn around. The "Add Coolant" light came on, and my temp quickly rose to 1/2. WTF? I proceded slowly, and my temp gauge slowly lowered down to about 1/3.

There it stayed until I got back into town (i.e., slowed down below 40). and the temp gauge started going up. By the time I got to my garage (4 blocks into town), it was a 3/4. I let it idle for a little bit, and the temp gauge went down, just a tad. I shut it off.

The coolant was boiling, and dumping everything into the overflow tank.

It has done this EVERY time I've driven it for more than 20 minutes lately. Especially if I go above 80, even for brief periods of time. And it awlays happens EXACTLY like the described above.



The only thing that I can think of, is that maybe my fan sucks? I'm not running an airpump, and i'm only running a single pulley (I know, it's bad of me, but it never malfunctioned before). I'm gonig to be ordering a dual pully next paycheck.

How do you tell if your fan is bad? and would that be causing my problem?


I NEED ANY HELP ANYONE HAS TO OFFER. Thanks.

jimmyv13

The coolant was boiling into the overflow because air has replaced the coolant in the system somehow. How is the radiator cap or the whole cap assembly for that matter? Is the radiator in good condition?



If your fan was bad, it would overheat in traffic not running it hard.

The Spyder

iTrader: (8)

Replaced your radiator cap recently? First thing I did- worked awsome.

TwEaK

iTrader: (6)

Wonko the sane if you in really bad need of a dual alt pully that i can sell you as for the over heading problems it could just be a small leak somewhere along the radiator like what happned to my dad's FD
TwEaK

BlaCkPlaGUE

Yep, a skipping belt on the pump, or my best guess, contaminants..

Alot of times lime and **** builds up inside engine water jackets and especially the rad, combine this with a bug littered radiator and you'll have yourself coolant issues. Heat best dissapates through the most surface area the heat has contact with. This also is the case with cooling, less surface area exposed, less heat will dissappate. So if the inner walls of the rad are clogged with lime deposites and ****, its gonna take forever for the conduction of heat.

I don't think I need to explain this, but take the rad out, buy a nice 2L jug of CLR and seal off the rad so no liquid can escape. Fill it with like half clr and half mineral water or something, or just use all CLR and let it sit overnight. next morning flush that **** out.

I've never tried this, but if someone has a better idea let this guy know.

ilike2eatricers

^ Just making sure but did you mean distilled water instead of mineral water?

cmanasseri

Sounds like your fan clutch is bad. See thread below.

https://www.rx7club.com/showthread.p...clutch+problem

WonkoTheSane

iTrader: (2)

The radiator cap is new from Advance Auto, about 1 month old. Should I be using a Mazda OEM one?

The radiator flows good. It doesn't have any leaks that I've noticed, but I haven't had it pressure checked or anything.

One additional thing that I noticed was that my "air bleed screw" thingie on the radiator is leaking VERY slightly when the pressure is up... dunno if that has anything to do with it, but I doubt it.

Oh, and last night (before the run), I had it idling for about 45 minutes.. Never went above 1/4, if that helps anyone.

BlackPlague - I don't think it's that, especially in the engine, as it only has 6000 miles on the rebuild, and i pressure washed the housings and irons when I rebuilt it. The radiator flows really nicely (when I put the hose to it flush it out before I installed it), so I don't think it's that. I keep it pretty clean, too, so I know it's not caked with bugs..

So the question is, how do I tell if my clutch is bad on the fan? According to Mazdatrix: "These go bad in two ways - either seized-up, which is very hard on the water pump and belts (and very noisy), or they are free-wheeling, which gives overheating while stopped or slow driving."... but mine only overheats while city driving AFTER it's already overheated on the highway..

TwEaK - You have a PM.



Damn i'm confused..

Also, I know that there's no air in the system (when I start, anyway), and I'm using a 50/50 mix of Prestone antifreeze....

SureShot

The fan clutch uses a silicon oil viscous fluid in two chambers inside.
The Bi-metal strip on the front bends outward as it warms and opens the valve from the reservoir side to the clutch side.
Centripetal force provides the pumping action to move the fluid.
When it sits for a few hours, it will spin the fan briefly on startup, then freewheel.
After 100,000 miles the bearing seals inside wear, and the bearing lube starts to weaken the clutch fluid's grip.
Both the S4 & S5 clutch freewheel when cold.
The s4 clutch increases it's bite gradually with temperature rise.
The s5 clutch is more on-off. (It just coasts until is gets warm)
Once they are warm, the fan speed goes up with engine speed to about 4000 RPM.
As the engine revs higher the fan stays at ~4K.
If your warmed up fan only revs up to ~2500 RPM, it's bad.

YearsOfDecay

YES GET THE OEM CAP... I have NEVER found an aftermarket cap that works... I got a supposed OEM cap from mazdatrix, but it didn't say mazda on the box and had japanese writing all over it, gues what.. didn't work.. it wouldn't let the water flow back through the system from the tank when you shut the car off and the upper radiator hose would suck shut every night... The one i got from Advance leaked and the car ran hot. just get the factory one and be done with it.

Any leaks on the stock system, any, will cause the coolant system to work inefficiently. The pressure keeps the water from boiling until a higher temperature, if you have a leak, it will allow boiling at lower temps.

If your clutch fan is siezed up, it will roar like a banshee the whole way up till redline... this is moat unnerving. It its worn out, you won't hear it at all. I good clutch fan will give that rrrrrrrrrrrr sound until about 3-3.5K RPM when the engine is hot and you won't hear it when its cold.

When the car is good and hot, shut the car off and reach in and spin the fan... if it spins freely, its shot. When the fan is hot, it should have some resistance on it, but it shouldn't be tight either.

I just replaced mine because it was locked up and screaming like a banshee at all times.

sounds like it isn't working cause what you describe is exactly what my car was doing with the E-Fan on it. With my front mount, the e-fan just didn't have the moxy to do it and as soon as you'd get on it, the car would heat up but it was fine when you started it, idled it and didn't beat on it , but as soon as it got hot, it stayed hot. As soon as i put the stock fan, a working stock fan, back on, it was A-OK!!!

SureShot

Also - The oil cooler is responsible for over 1/3 of the engine cooling.
1.Are the Oil Cooler fins clear of debris and clean?
2.Does the Oil Cooler thermostat function properly?
3.Are the Radiator Fins clean of debris?
4.Is the Stock Bottom shroud still in place?

Sir Rupert Hobo

i'm with jimmyv... i really think there is air in the system... how do the hoses look after it's ran hard? are you sure you bled the system correctly? if you did, then i would check what sureshot mentioned about the oil.

WonkoTheSane

iTrader: (2)

Awesome, I love it when I get a lot of good feedback. Thanks to all of you..

YearsOfDecay - Thanks for the insite. I'll pick up a OEM cap today, check the fan ASAP. I'll also see if I can find a plug to make sure I get a good seal on that "air bleed valve".. Caulk/RTV is necessary.

Sureshot - that clears up a bit of the mystery of how they work... I was figuing pixie dust or something.. I'm going to use YearsOfDecay's method of testing the fan, but I'm starting to think that the fan is on it's way out...

I know the oil cooler is working properly.. well, I know at least that it's getting nice and hot, and not packed full of bugs... that's about hte best I can do without a pressure check. About point two, I didn't realize that the oil cooler itself has a thermostat, how/where do you check this?

Right now I don't have the stock shroud on. I'm going to make one out of aluminum as soon as I can, but the stock shroud is long broken. It wasn't overheating before, however, it just started that about two or three weeks ago..

Sir Rupert Hobo - I'm pretty sure that it's not just air in the system. At least two or three times, I've filled up the system without the thermostat in, and then ran the motor for ~30 minutes with the cap off to make sure the water was cylcing. I don't see how air could still be trapped in the system.


One thing to note, I think this is normal, but I if I watch the car with cap off, and I rev the engine, the water level goes down, and if I let off the throttle, the water level rises, and spills a bit out of the top.. It's not really bubblly or anything, So I'm pretty sure it's responding normally..

Again, thanks for all the help

YearsOfDecay

This is my bet.... 50% of your problems are being caused by your fan, 40% are being cause by not having the underpan on, 5% from the autozone cap and 5% from the leaky plug.

As for the under pan.. you don't have to have the whole engine bay covered like the factory pan, you DO have to have from the front intake to the radiator completely closed in to forse air into the radiator.

Here is what HIGGI did for a custom metal pan:


Over the winter I'm going to be making one of these myself!

The action you described for the water is normal. But, if you're cap isn't correct, you may be getting air in the system. Get the new cap, put it on. then take the cap off the water neck cap off and fill er up from there. run the car, completely let it cool and take the water neck cap off and fill er again untill you got NO AIR in the water neck. I'd get a new flat cap for the water neck while you are at it. after you get the system full and no air in it, don't take the radiator cap off, just the water neck cap.

hondahater

iTrader: (2)

I have never had a problem overheating due to my underpan (or lack there of) however somepeople really swear by them so yeah you may want to get one as well as a cover for the top if you don't have one already! I also have the autozone caps and never had a problem with them either!

Tiers

Wonko: "Right now I don't have the stock shroud on. I'm going to make one out of aluminum as soon as I can, but the stock shroud is long broken. It wasn't overheating before, however, it just started that about two or three weeks ago.."

You do need the fan shroud on for proper cooling/tunnel effect. Even if you didnt have it on before this can be worth a good portion of your heat prob. Only a larger rad or extra electric fan can get the same cooling effect that the fan shroud gives you. Also same for the belt prob. There is a lot of slippage with single belt at higher rpms causing waterpump to not work properly/slipping/cavatation. And yes as well even a small leak like the bleeder screw(or any other leak you have) will effect cooling due to pressure loss in the system and air entering in its place.

1) fix all leaks
2) get dual belt
3) get a fan shroud on there
4) OEM Rad cap (all otheres suck)
5) HAVE FUN!

KNONFS

iTrader: (14)

That ain't it, been running non OEM cap for over a year without a problem.

WonkoTheSane

iTrader: (2)

I was thinking of the underbelly shroud when I wrote that,s orry. I've never ran it without the fan shoud on. I'm thinking it's definately the fan. I'm trying to price a new one now, the best I can find is 160 from Advance. Anyone have any good suggestions of where to get one? I won't have that kinda cash until at least next week. I know you can run E-fans, any cheap commonly-availble-from junk yard ones I could geT?

I REALLY REALLY need to fix this ASAP. . I got burned today pretty badly on the face, when my resivior cap came off to easily after the car overheated. I hit the overflow hose, and I must nothave gotten it on tight last night, as it exploded and i got a face full of steam.. I'm just llucky I was wearing my glasses, or else this would be A LOT worse than it is... and it's not too happy as it is..

Sir Rupert Hobo

i agree... as long as it's the same PSI rating(or very close) it's good enough.
i've had my non OEM one for 2-3 months. works great.

the T-stat on the other hand....

hondahater

iTrader: (2)

I think some people use the fiero fan for a good junk yard fan however If I where you I would just get (if you have fc's in your junk yard) a stock fan from another one or get one off someone that is parting their car out in the for sale section if you can wait that long. Good luck man and sorry to hear about the face.

ddub

Escort fan works wonderfully too. Got mine for like 10 bucks looked brand new and was from a 96 escort that was really clean, just totaled in the rear.

rs_1101

its not the fan. if it was, you would have overheated at idle. at speeds above 30mph, the fan is utterly useless, as exterior front bumper pressure will force air through your radiator. check your car for error codes while at running temp.

did you say you had a new radiator? if not, check the old one for cool spots. its well known that our stock rads suck. its really strange to see that you overheated on a togue. what were conditions? was it hot out? dry? low air pressure? these can cause rotary overheating. my cars running temp is about 60% at sealevel, as what it is in say.. palm springs.. high desert. still..

when you rebuilt you replaced coolant seals, correct? is coolant clarity still present? (is the coolant green.) think is there anything else youve done that would affect performance since the overheating began? maybe youre just running really really lean? are your exhaust gasses unusually hot?

edit: also put the underpan back on. theres a chance at high speeds that suction under the car would draw air away from the rad.

jimmyv13

I agree, don't bother with the fan, your's is fine. I'd figure out how to seal up the bleeder screw, allowing ANY coolant out of the system at high temps/pressure will let air in at lower temps/pressure via a vacuum created. The coolant is supposed to be pushed into the overflow tank when hot then sucked back in when cool. When there's a leak somwhere, it's easier to suck back in air rather than pulling coolant from the tank. You may even have a leak in the line going from the radiator cap assembly to the overflow tank. Looking for cool spots on the radiator spots is a good idea too. A good system flush may be in order.

Get your system all filled up and bled. Make sure your overflow tank is at the full line with coolant. Go for a short, 4-5 minute very spirited drive. Get the RPM's high and run it hard. When you stop, pop the hood and look for coolant coming out anywhere, even small leaks are not good. It may not be dripping, but look for steam or anything that would indicate that coolant is getting out of the system. See if your overflow tank is full.

rs_1101

ive got a small leak between water pump/housing, it rarely even actually leaks, and my car barely gets up to running temp. the needle barely scrapes the bottom of the guage.. maybe cuz im running rich as hell.

RotaryForce13B

I had an overheating problem that was a nightmare similar to this, and I ended up changing EVERYTHING on the cooling system. Water Pump, Hoses (all of them), Rad Cap, Thermostat and Installed E-fan with thermostatic control. Mine turned out to be the Rad Of course it was the last thing I replaced.

I wouldn’t think you need an alternator double belt under drive pulley because the water pump. I bought mine so my alternator would stop slipping a 7k RPM's (Screeeeeech)

On a S4 there is no doubt if you fill up the cooling system with out removing the bleeder screw it will have an air pocket and coolant will not circulate.

Now I know you just did a rebuild and it’s not uncommon for the water seals to get slightly out of place when building a motor. You also said that it smokes on start up? That could be a sign of coolant in the combustion chamber. Is the smoke white? Does it smell kind of sweet? Is it hard to start after a good run?

One of the things I would do would be to pressure check the cooling system you should be able to rent the tool at a local parts house.

Hope this helps Good luck!