Thanks to you both for such quick replies. Jim you are right that .7 bar is a little over 10 psi.
This question spawn from trying to get a stable 15-20 degrees out of my coolant system. Jim I took your check list and went to work. My car has been consistently running a stable 195-200 since we started getting summer temps and I was determined to get her to normal based on the discussion we all had around ALfemale's Spider overheating.
To be honest about it, there have been some late nights, some cursing, and absolutely no change whatsoever. I took the checklist you made and walked down it as well as any other possibilities.
The situation was a recent performance build running 15-20 above normal. New H2O pump. Radiator rodded and cleaned out. Restrictor in the bypass. All hoses as they should be. Electric fan as a pusher. Recently replaced thermostat.
First, thought the radiator cap must be bad. She now has a new 7psi....so maybe this is the root of this evil.
Second, I swapped the radiator. I have a spare that is in excellent shape. Fluid was clean. No oil or sign of blown head gasket. Moved fan to new radiator as pusher.
Third, found a disc type thermostat and replaced 180deg. Other one did not have the disc on the end to block off the bypass.
Fourth, played with timing to ensure no retard, enrichened the carbs, and swapped plugs.
Fifth, swapped sending unit to water temp guage (I had an extra sitting around), pulled radiator and put the original back in, and setup fan as a puller inside the engine bay. I tell you I have less than a 1/4 in clearance between that fan and the front pulley.
Over all of this I have ensured 50/50 mixture. I am stumped. I am thinking either the guage itself, the water pump bad even though it was recently replaced, or something internal brewing.
Hey John, a Audi/BMW enthusiast friend just told me about a product called Redline Water Wetter that makes the claim of being able to drop the temperature "up to" 20 degrees. Anyone every heard of this or tried it? I'd love to hear how it rates.
I am also looking into another fan with higher CFMs.
FWIW, of what seems like a thousand waterpumps I've changed over the decades, I've seen only one that had a bad impeller. If it's turning, it's pumping.
What I didn't see in your post was if the cooling system was bled. Can't stress enough how important this is. The pic shows 2 of three bleed screws; the third is on the heater control valve (pic available if you need it). Do you need instruction on the bleeding procedure?
All of this umm.. frustration? is based on the reading of a temp gauge whose accuracy can (almost) always be questioned. But changing the temp sensor is no guaranty that the reading is now accurate, but it helps.
Pardon my occasional brainfade - I forgot two things.
Sarah - Yes, I have heard of water wetter. Although I haven't used it, friends of mine have. Some say it works, others don't. Personally, I think that all the cure-all 'mechanic-in-a-can' products just attempt to mask the root cause of the real problem.
John - Radiator caps have nothing to do with the cooling system temperature; that's the thermostats job. The cap's job is three-fold; provides access to the system to add coolant, increases the boiling point of that coolant and acts as a pressure relief valve if system pressure gets too high.
You know, every year around this time (summer!), there are lots of folks with Alfas who experience higher than normal temperature readings. While I certainly understand that the ambient temperature is higher, why is that such a big factor when we have fans and good coolant, etc?
It seems to me that if it ain't the bleeding that's causing the problem, the only real common thread here is the fan. Both you and Sarah have an aftermarket electric fan. I have been occasionally tempted to do that too, but I remember the trouble I had with my Track Alfetta with the 'hot' 2L. It was always over-heating when it wasn't going fast enough, even with a manually switched electric fan which came from a Milano.
My Spider 1300 has overheated once or twice, but that was because the leaky radiator lost too much coolant, or from a burst hose.
It's a drag to overheat, and overheating regularly is a dangerous event that can lead to a blown head gasket or worse!
Papajam...you seem to have lots of answers. What do you think? Are these electric fans likely to be the main problem?
Thanks for the pointers. It may be a bleeding problem. I did bleed the one behind the thermostat but not the other two. Went to higher psi cap and no difference.
On the cap, my engine builder said if you run too little psi cap or your cap inner seal is worn and not generating enough back pressure, could result in low flow and running warm.....but not overheating.
He said the same thing on the longevity of the water pump as well as the guage being possibly defective.
I don't think the fan has anything to do with it providing its properly placed and the thermostat to power it is set up correctly and not running all the time. I can say that the electric at idle pulls way more air than stock. And at speed, I believe there is far enough flow to cool the radiator without any fan...mechanical or electric. To add to this she ran perfect all summer long last year with the electric pushing. Prior to that I was running a two blade mechanical w/o problem.
To clarify.....I am not overheating.....but running on the warm side according to the guage. Not talking about 260....but rather 195-205. Its probably nothing more than the guage, but with the investment in time and money, I certainly would like to see the guage reading at 180. And it does represent a change from last summer.
So with that said, I am off to bleed the water pump. Hey Jim....where is that heater bleeder? Can you do it from the intake manifold inlet?
Lots of answers? All I have is some experience and a few 'been there, done that".
No, I don't think that electric fans are the main cause but I think they can be a contributing factor. Case in point; prepping for a track day at Bridgehampton. Forcast was for 100 deg temps and humidity in the 90s. "Too hot for trackday with a stock fan", I thought. So I installed an electric pusher fan in the GTV. During the first session, the coolant temp reaches the low 200s. I'm not a happy camper. So I yank out the fan and in the second session, the temp tops out at 180!
Granted, todays electric fans have smaller, more efficient motors than the 6" diameter monstrosity I installed but the principle is the same; insufficient airflow. Switching to a fan with a higher CFM rating may help some but only because it's pushing more air thru the portions of the radiator that aren't blocked. Now at idle, the portions of the rad outside the diameter of the fanblade have no airflow at all. This is why, IMO, the stock fan with the fan shroud can't be beat.
That's a very good point! I tend to agree with you. But, please don't water-down your terrific knowledge of Alfas! Anyone who knows their way around a 105/ 115 Alfa these days is a rare bird! I know that I (for one) really appreciate reading your posts!
I just had a sort of a side-thought (probably my only good one so far today!):
Do either you (John), or you (Sarah) have a front license plate or have you got any other non-stock airflow blocking devices like fog lights? Is you lower valance (the part under the front bumper) bent upwards? Do you have the stock front sheet metal, or have you added an air dam?
Obviously, what I am thinking only applies when you are driving at speed, not while sitting in traffic...but, if your car is running too hot even at speed, blockage of the normal airflow could be a problem.
No doubt Jim is the best. I really enjoy reading his posts and I am very confident in his word. And when I think of who to ask a question on the board, Jim and John (Roadtrip) always come to mind.
I have no restrictions to the front air intake and no damage. Also nothing up there to block her from getting air. Its totally stock radiator forward.
Sarah's car is having some serious overheating issues that I am fortunate to not have to face as of yet. For me its a very stable 195-205 on the guage. Its really not varying off that at all. In traffic or running down the interstate. And the car runs perfect and very fast. Spark Plugs showed a great mixture and nice tan.
So...I did bleed the water pump, heater, and thermostat. No change. I put her to a little test. I decided I needed to rule out exhaust leaking into the coolant. IAP's headers, new studs put in by my mechanic, who knows....maybe a water jacket issue on one of the studs. So I took her down the interstate at 110 mph for about 8 miles. Usually you won't find me driving over 75.......but, I thought I would air her out. Still no overheat.....just the 195-205 steady as a rock.
I think that rules out a headgasket problem because coolant would have been flying out the overflow and surely I would have some other symptoms. Should eliminate the water pump as well. Bleed is done. Thermostat replaced with proper disc for bypass and is 180 temp thermostat. Sender changed. If its the radiator....then I have two that are bad. Near proper pressure radiator cap. Timing and mixture ruled out. If I had a stud in a water jacket....I think I would see leaking coolant after cool and I don't. I think that takes it down to the guage.
With that said.....I am fortunate to not be in jail tonight. And I think I will get another guage and give it a try. Who has one for sale w/ chrome bezel?
I think I might have an extra one around here somewhere, but I may want to replace the one I have with the extra one, because the one I have in the car has a burned out light bulb. It's just as easy to change out the whole gauge!
I am having the same problem as mentioned in this thread. My '77 Spider 2.0 is built up to get about another 20-30 HP, put in a new radiator and water pump when I did the motorwork. It was running at a stable 180 now running at 195-205. I swapped out the thermostat, same result. Changed out the sending unit, and it actually reads a bit higher. So much for accuracy there. I will be putting in the old sending unit back in this evening. Bled the system each time also. I richened the carb mixture slightly also. Re-torqued the head, and checked for coolant leaks as best as I can. Nothing seen. This evening I will be rechecking the timing. Is this all just coincidence from the weather getting a bit warmer? Hate to think so, as we had some hot days here before and the temp stayed at 180. Problem seemed to get progressively worse after wire lead fell off of sending unit a few weeks back. I will be checking the wire also. Guage read a bit over 180, then 195, until where it is now.
My heart goes out to you Ken. This problem is driving me crazy and putting a paul on driving experience.
My car also is 'tweaked' to get more hp. but that seems to scarifice cooling temps. I watch what my themostat does directly proportional to the weather. What is happening with new radiators or higher horses that changes the car from a consistant temp to one that is so affected by ambiant atmosphere? Can I only drive my car now when it's 75degrees and under?
Timing is my next project, I have a larger fan with more CFMs available to me, but I'm wondering if a motor mount fan isn't a better idea or to have one in addition. Which do you have? I have a lame theory that when it is really hot outside and you have an electric fan mounted in front of the radiator that it is blocking air coming from outside and blowing hot air back in toward engine which isn't channeled out well enough and is raising temperatures. The hope is that an engine mounted fan or an electric fan mounted behind rad will pull heat away from engine... again just a theory.
Alex, I do have a front licence plate and I am beginning to thing there might be some air flow blockage somewhere, and if that's true than a fan not up to par would be a big culprit.
I am just running the factory plastic-bladed fan on the pump pulley. The electric fan shouldn't be blocking any air, the framework on these units is usually pretty thin that it shouldn't cause a problem. As long as the fan is moving air across the radiator toward the motor, either by pushing or pulling it (front or rear of radiator installation), you should be in good shape. I'd think that the license plate should not effect it either. Is your fan thermostatically controlled or does it have a manual switch? It may not be turning on automatically when needed.
My rebuild is relatively new, I finished it about 3-4000 miles ago, and what was set as timing then may not be what a broken-in motor needs now. Cam timing may need rechecked also. A fun evening's work. I have the 10.4.1 pistons, 11mm street cams, Bosch electronic ignition distributor from Centerline, and a Dellorto carb setup on Euro intake manifold. Factory split exhaust manifold also. Timing was initially set at 5 degrees BTDC at idle, max advance around 40-41 degrees on 93-94 Octane fuel. Pretty close to Euro carbureted specs. Car runs great, just want to cool it down a bit.
Anyone running anything similar and what timing is your engine set at?
I am going to doublecheck the thermostat and be sure that the bypass problem mentioned previously is notthe culprit.
I just wanted to post a note about the "watter wetter" products. I have used them in several of my cars - they are a surfectant that breaks up small air bubbles caused by localized boiling or stirred into the coolant by cavitation of the waterpump. I don't think they will fix an overheating problem but they seem like cheap long term insurance.
Be careful about putting a colder-than-specified themostat in the engine. Both the SPICA and L-Jetronic rely on temperature readings to set fuel metering. If the engine is running at colder than "warmed-up" temps, the FI might read that as a still warming up mode and enrichen the mixture unnecessarily.
BTW, my 74 runs very happily down the South Dakota "Autostrada" on a hot day with 195-200 deg coolant temps. Mid-life engine, stock thermostat, stock plastic fan and shroud, ignition timing correct, and mixture correct.
I'm with Papajam . . . . . modifying the engine from stock in an effort to try and band-aid a problem often just creates more problems. Find the root of the problem and fix that.
Even with the 160 thermostat I am running 180 very consistantly until I hit a traffic jam now and then only up to 205. Timing is 7 degrees BTDC where it is supposed to be.
Good information to know about temperature and gas mixture. Thanks road trip!