MachSchnell

Well, after taking out the car to run it a bit, after a moderate drive (10 minutes, some highway, some stoplight, on boost maybe 50% of the time) with A/C on, the car began to run hot...at stoplights it got up to about the third line on the gauge (didn't set off the red light, and held pretty steady) and would settle back to the 2nd line to mid 2nd/3rd line when I would get back up to 20+MPH, but when I got home, out of curiousity, I let it idle with the A/C off, and it got up to the point where the red warning light came on...obviously an issue...does the 951 run traditionally hot under such conditions (in Fla, ambient couldn't be more than 85 deg right now, probably less) or should I really be worried. My obvious first thougth is a fan issue, as it tended to be more apparent at idle (btw - A/C would get mediocre and blow tepid at idle as well...a bit colder than ambient so I'm assuming it's a temp issue rather than refrigerant issue) than at speed...have people had fan issues, or should I consider upgrading to a better electric? Is this something that quite a few people have run across, should I just check my fan grounds, or T-stat, or might the problem lie a bit deeper?

All suggestions/stories welcome!

Jason

MachSchnell

Pursuant to my impatience, after posting this I realized that there was also a very noticeable bubbling sound, which it seems is perhaps indicative of air in the system, which I will bleed and refill this weekend...any procedures other than keeping the heater running full bore while doing this? I have a full flushing kit, but given the intricacies of the plumbing here, I'm wondering if perhaps there might be a more efficient way to bleed and flush the system without tapping water to heater core lines...I'm getting ready to order my service manual, but obviously this is a relatively important issue, so please forgive my questions until I get situated with service info...also, previous cars I've worked on have had 'burpers' to let air out of the cooling system...is the 951 so equipped?

Thanks again, (I'm a bundle of questions tonight, prolly a bit overprotective of my new baby)

Jason

adrial

Yeap, I'd say flush/bleed the system.
Make sure the coolant you use is phosphate and silicate free.

There's a bleed nut (that I seem to have forgotten where it's located...its near the fingers of the intake manifold though...towards the distributor cap)...anyway, fill it with coolant, then open that up. Some like the car to be jacked up in the front...I put my car on a hill. You want the front end to be higher than the back, though. Then start the car and run the heater full bore like you said and wait until you see just fluid coming out of the bleed bolt (no foamy stuff anymore)...then close the bleeder and it's test drive time.

If you hear bubbling you should bleed it anyway, but you should also make sure both fans are running when the car is at the top of the middle range (the normal operating range). If the fans aren't running, the car will overheat...pretty simple. After thinking about it for a few mins, I would definetely check the fans as that sounds like a likely culperate.

Don't let the car get as hot as it did in your intial testing, bad things can happen. When you turn the car off, the engine (well the coolant) actually heats up dramatically because the coolant circulation is cut off...so if it was in the red when you turned it off...who knows how much higher it went after you turned the car off.

MachSchnell

Well, it kinda snuck up on me, as it was running top line for a while, so I parked it and shut off the A/C, so I was expecting a drop...unfortunately that wasn't the case, but it won't happen again...the fans will be first check, but after doing some research it seems air in the system might be a logical culprit as well given the gurgling even after I shut off the car...I'll be doing a full flush and bleed as well...Adrial, I remember reading about your woes in some earlier overheating posts...Water Wetter was an oft referred cure, and I've had great success with it in the past in track and street cars, but if we have a full aluminum system, can anyone suggest a reason not to run straight water and water wetter, without coolant? Being a floridian, I've never been an advocate of coolant as anything other than an anti-rust/corrosion tool, so if we're all aluminum, seems like just water and Redline would be an optimum mix...

Also, I found the bleeder (****, looks like nobody ever used the damn thing) and will expect to use that during the bleed, but you referenced running the motor with the bleeder open...is this the recommended procedure??? I had always run, bled, closed, run, bled...should I just leave this open and wait for straight fluid to come out?

AutoXdriver

Hmm, I'm having similar problems with my "new" 951. No bubbling noises though and it was HOT outside (close to if not at triple digits). I'll have to check the fans.

Jason please post what you find to be the problem and I'll do the same, maybe we have the same problem.

Alan

951carter

yes, leave it open when running but keep an eye on the level in the tank, don't let it go dry. Also make sure to turn your heat on when bleeding. It doesn't hurt to slightly elevate the front of the car either.

MachSchnell

Hmm, totally counterintuitive to my previous 240sx stuff, but then I should also leave the cap on the reservoir open wh
ile performing this procedure? Interesting. First concern is fans, as at speed it seems OK...anybody ever upgrade to aftermarket fan setups, I've had great luck in the past, lower amp draw and much better cfm on newer elec units, but anybody have recommendations on good fits, easy installs etc for aftermarket electrics?

Jason

Bri Bro

If the fans are working, air is removed from the system, and the coolant levels are correct, the factory fans will keep the engine temp down even under heavy load.

<a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=18&t=001111" target="_blank">Checking fan operation</a>

StanUK951

Jason - I noticed a gurgling noise on my car after I replaced the rad. It went after bleeding the system but bleeding didnt really have an effect on temps.

My car has a different problem where both fans come on together when the gauge gets to half way. They then cut in and out until the needle is below the 1/3 mark. I suspected the relay and changed that for a s/hand one but it made no difference - might try a NEW relay and see if that helps.

By the way, dont buy the factory manuals, go to <a href="http://www.ninefiveone.com" target="_blank">www.ninefiveone.com</a> and download em! May take a while if you only have a modem connection though.

toddk911

WOW. I was going to post an overheating issue as well. I guess these recent high temps pull out the overheating gremlins in a system. I am also in FL (Orlando) and it has been REAL HOT. It just overheated a couple of days ago, at stop lights and has been intermitent. i.e. it will hit ¾ then settle to ½ or ¼ and a couple of times the light actually came on, but gauge was reading ½. (that’s why I didn’t notice it). No leaks, new water pump, and fans seem fine. My ac also is barely cool at idle as well, I just figured that is due to 95+ temps outside. Could it need to be bled? (vapor lock) I didn’t notice any gurgling. <img src="confused.gif" border="0">

adrial

Reason not to run water wetter and water is that will boil.

Coolant lowers the freezing point as well as raises the boiling point.

To drain coolant from the system, most recommend removing the lower radiator hose instead of using the drain bolt because the drain bolt strips so easily.

Good luck!

The post you read about with me involving an overheating issue was I think me saying that running an extra ground engine to battery caused my temp gauge to read lower and not jump around when different accesories were turned on. It sounds like your car is actually overheating though, not just a temp gauge error.

Maybe that burbling was the coolant/water boiling??? Hmm I think thats a good possibility..

--adrial

MachSchnell

Good points, I think I'm 90% sure after some logical thinking (last night I was getting a little paranoid...first day with car and all) that it is a fan problem, so first issue will be making sure fans run, if not, replacing relays. Anybody have suggestions for good relay replacement source...I've always been a junkyard fan, but in cars this old, junkyarders tend to be pretty messed up...so, if anyone has a donor car, or know a good source, relays are likely in the future...but, I'm a BIG fan of aftermarket fans, the CFM alone is worth the cheap cost...anybody running them with good stories, fitments, etc?