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I have an 88 Grad that is over heating. No oil in coolant or coolant in oil. At first the temp guage showed it was getting hot, then suddenly it dropped back to normal. I replaced the thermostat. Now it seems to only overheat in stop and go traffic, and runs normal at freeway speeds. The car has A/C, but no drive belt. The fan belt is good and so is the tension. Any ideas?
 

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Alfa gauges aren't known for measuring things with absolute certanty. Consider cleaning & tightening all connectors between the sender & the gauge. And the sender's connection to the engine (where it is screwed in) has to be electrically certain, also.

Once you're certain that the gauge is reading correctly, you should consider removing the radiator and taking it to an "ole-fashioned" radiator repair shop for cleaning.

The Alfa radiator is a very sturdy unit. So, assuming it is original to your car (quite possible) it is nearly 20 years old. Even assuming it has received proper maintanance all those years (less possible), it's due for a thorough cleaning. Flushing it with a garden hose will not do a good enough job. A real radiator shop can either use strong chemicals or open it up to 'rod it out' (physically scrape the inside of the core clean). I had that done to the radiator in our '84 Spider. Costs me less than $50
 

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The only thing beyond that I would suggest or ask:

Did the t-stat you put in have the same heat range as the one you took out?
Did it go in facing the correct way?
Did the coolant system get properly bled during the refill?
 

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If it in fact keeps overheating, I would worry that you have some level of blown head gasket possibly. I'd do a compression test and a cooling system pressure test. Is it using water?

Andrew
 

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Gvann,

My 86 spider began running warmer after I changed the t-stat and hoses. I had these parts from the former owner, was off work for a couple weeks and got amibitious. Now that summer is here, I noted the temp gauge would be around the first to second tick mark right of 175. Knowing that the gauge may not be real accurate, that pressurized water boils at a higher temperature, that the radiator was flushed and rodded three years ago, and the only change made was the t-stat and hoses, I wondered if the system had been properly bled.

So I got my shop rags, metric wrenches and bled the radiator again. This time, I turned the heater on, opened the top plug on the intake manifold and let her bleed. Air blew out immediately, and I waited until the fluid squirted out without any signs of air.

You know what? The temp gauge stays right at 175 or just slightly above, even in stop/go traffic.
 

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My '89 Quad with 61,000 miles is still giving me some overheating problems. I have replaced the water pump, thermostats and hoses. It still ran hot; that's when I noticed the oil film in the overflow tank, and moisture on the dipstick. So, head gasket replaced, radiator cored, and the heat still rises, but much more slowly, especially on a cool day. Usually, the motor warms up quickly, goes just above 175 to almost the first hash mark, then comes back to 175. But as I drive on, it climbs slowly, usually to the second hash mark. That's when I turn the heat on and that helps stabilize the increase. On a hot day, however, it gets bad. Just the other day I was heading over a local 8500 ft. pass (the valley here is 6200 feet) wih the outside temp at about 95 deg. Halfway up, the motor hit about 210-225 deg. and the pressure blew coolant out the radiator cap. I decided it wasn't worth the trip, so went back down. Using the motor to help brake the car, the temp was back to 175 when I got back to the bottom.

A buddy here has an '85 Graduate with about 35,000 miles and has never had an overheat. He suggested taking out the thermostat. I hesitate to do this as it may not be so simple a fix on an L-Jetronic car as it would be for a carbuerated motor. So my questions are, is this a good idea, and, since I suspect I need a new O2 sensor, could this be a culprit for overheating?
 

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It could be dirt/oil buildup on the radiator. My spider was running at 215 - 220after about 30 minutes driving with 90+ ambient temperatures. I swapped out the electric pusher fan because I suspected that the one I had installed may have been insufficient. When I pulled the radiator I found a good amount of oily dirt on the fins. I cleaned it off with degreaser and a garden hose. The engine is now running 30 degrees cooler. I suspect that cleaning the radiator had a bigger impact that swapping out the fan. I drove 360 miles on Saturday including some spirited stuff on mountain roads and the temperature climbed to 190/200 for a while but was back to about 180 at 80-85 mph interstate cruising. I do not worry so long as it stays below 210. The combination of a pressurized system and anti-freeze will prevent boiling. I get concerned about the diminishing safety margin when it heads towards 220. Redline water wetter is supposed to prevent hot spots in the cylinder head at high coolant temperatures. I use it.
Ed Prytherch
74 GTV
79 Spider
88 Milano Verde
 

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Mark,

Do not remove the thermostat from the cooling system. I know that we all got away with it on our Detroit iron 30 or 40 years ago:rolleyes:, but it wasn't correct then and it is not correct now - especially with engines that have cooling systems that are not way over-engineered (like any of the higher-revving, smaller displacement, higher output units from Europe or that have evolved in the US over the past 20-25 years).

The thermostat is an important component that is required in any cooling system that has one. It ensures that the engine operates at a proper temperature - neither higher nor lower than required. That's right, the thermostat helps in the cooling of the engine by increasing the residence time of the coolant in the radiator.

Also, without the thermostat, an engine may not run hot enough. A proper operating temperature is important to all engines, but is especially important to engines equipped with a computer-controlled fuel/ignition system. Sensors that provide information to the computer need to be at operating temperature to function properly. If there is not a thermostat, or if someone stuck in the '60s installed a thermostat with a lower temperature opening point, then the system will not function properly (AMHIK).
[/soapbox]

gvann and Mark,

What are you using for coolant? Does the electric cooling fan come on when the engine gets hot? Is airflow to the radiator blocked? How is your catalytic converter?
 

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Ed and Ron, thanks for the feedback.

Ed, I hesitate to feel good about any Alfa running at high temps., esp. in the 190-210 range. Over time, isn't there danger of valve damage, or general damage to the aluminum components? This is what other Alfisti have reported here on the BB. As mine moves off the 175deg. mark I start to get nervous. MAYBE, my mechanic did not do the reported work on the radiator as I described. Time for a gunk check and possible cleaning.

Ron, thanks for endoresement of not monkeying with the original set-up re: thermostats. I've been admonished on this by other Alfisti, so will leave it alone. My electric cooling fan operates fine, even comes on with a 5-10 minute delay after shut-down sometimes. Like I said, I should replace the O2 sensor and I'll bet the catalytic converter needs replaced, too, just as a general need. I use a 50-50 Prestone/water mix.
 

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Hey Folks, Just my two cents:

Silly question but are you sure that #1 your engine fan is bolted on in the correct direction, and #2, is your aux electric fan turning on under stop and go conditions?

I have had this happen before with some of my other spiders. Somewhere along the line the water pump is changed and a lazy mechanic bolts the fan on without checking if its pulling or pushing air.

If your car is dropping to a lower temp at highway speed, that says to me that you have an air flow problem... Over 30 mph the car really doesnt need a fan to cool off.. the ram force of air into the front dam is enough to cool the car...

So that would be my first thing to check. In addition, I would look at the aux cooling fan and see if it is turning on or if that fan is wired to spin in the correct direction... (You wouldnt believe the strange things I have seen with mechanic's trying to play electrician).

Also, I would pull the radiator (for the heck of it) and flush in the system. Most flushing compounds say that a complete flush takes about an hour... My opinion however is to drain the cooling system, fill with water and let it sit over night with the flush solution, then drain in the morning with tons of hose water. (you get lots more gunk out that way IMHO)

In addition, if you live in an area that gets really hot, Or has a very rich mineral content in your tap water, I would add some mild soap or commercial water wetter to your coolant to lower its surface tension and increase heat transfer.

High mineral content will lessen your car's ability to quickly transfer heat.


So in a nutshell:

1) Flush the system (just for the heck of it) and let it sit over night.
2) Pull the radiator from the car and let it sit with flush and then insert a garden hose with running water for 30 min or so to make sure you get all the gunk out.
3) Put coverings over the electronics in the engine bay and do the same with a running engine
4) use a mild soap or some other commercial water wetter, to increase heat transfer and use a summer mixture of coolant e.g 75% H20, and 25% Ethylene Glycol (Antifreeze).

Personally I use distilled H20 with water wetter and a 80/20 mixture of coolant. That so far has done a nice job of keeping the needle right on 175 and a little over when the A/C is on even on those 100 deg. days.

I hope this helped.
Cheers
Martin.
 

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High Water Temp

Hi Greg;

Don't mean to barge in on your thread but my 89 Grad has also been running "HOT" as of the last month.

My car use to run at 175 continually, but now it's running around ~215 after warmup. I ran the car last weekend with ambient temps ~100 and the gauge spiked towards 220 in stop and go traffic.

I don't have any leaks and the coolant reservoir level hasn't decreased hardly at all. Unfortunately I don't know when the PO did the last coolant flush, so maybe that is next on the list?

Any ideas, thanks in advance, Steve.
 

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Hi Greg;

Don't mean to barge in on your thread but my 89 Grad has also been running "HOT" as of the last month.

My car use to run at 175 continually, but now it's running around ~215 after warmup. I ran the car last weekend with ambient temps ~100 and the gauge spiked towards 220 in stop and go traffic.

I don't have any leaks and the coolant reservoir level hasn't decreased hardly at all. Unfortunately I don't know when the PO did the last coolant flush, so maybe that is next on the list?

Any ideas, thanks in advance, Steve.
I guess if you live in AZ you can remove thermostat permanently?
 

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if you remove the thermostat, block off the bypass hose, the thermostat shuts off the bypass when thed engine warms up, if the bypass is open, the radiator is bypassed by some cooling water.
cliff
 

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Steve, your problem is similar to mine, no eveidence of leaking although the temp wants to climb, more slowly than yours, though. When I was going to the 225 mark, that's when I found I had head gasket problem. But now, I'm thinking of 3 things: new O2 sensor, new catalytic converter, and a radiator cleaning. This last only because I wonder if my tech actually flushed and cored the thing when he said he did.

Does anyone know: will a bad O2 sensor and/or clogged converter bring on overheating?

As a final resort, though, I may revert to Cliff's advice and remove the thermostat and block the bypass
 

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Hi Folks,
Just my 2 lira's worth.

Any radiator that is 20 years old will have lost cooling capability, either because it has crud/deposits inside or crap in the fins.

If you plan to keep your car for a long while, I would recommend having your rad recored with a 3 row core. it costs about $250 and is a wise investment! It is becoming more and more difficult to find anyone that will recore a rad, if you do, get it done.

Around here they claim to flush (and I'm sue it helps some) and rod out the the cores (though I could not get the guy to tell me how he does it without unsoldeting the tank top.

The guy I went to did a flow test, I saw it and he said its full of crud. Boiling it out will leave you with thin cores.... So I went the recore route!

Original, dense 2 row cores, recore did the job with 3 row cores, looks OEM and I'm sure will last another 20 years.

TTFN Elio
 

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Thermo/Radiator

Thanks all for the replies.

Maciej and Cliff;

Should I take out the thermostat and block off the bypass value first or try the radiator flush/core initially? What are the caveats with removal if any?


Mark;

At what point did you notice the gasket was on it's way out? I don't have any milky/chocolate froth in either the rad cap, dipstick, or reservoir bottle...yet! No significant leaks in back of the block either as of now. To quote Pat Braden's Bible book that a temp around ~215 is nothing to be overly concerned about and it "could" be an air flow issue in which cutting behind that lovely black thick front bumper solved.

Steve
 

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One more time:

Do not remove the thermostat.

Do not remove or disable the bypass system.


Instead of re-engineering a system that is just fine the way it is, find the malfunction and fix it.

System pressure is vital for heat absorption – do a pressure test on the system to discover any leaks, and test the cap to make sure that it is holding pressure.

Fluid flow is important for heat transfer – make sure that the system does not have any blockage in the passageways, hoses, and radiator and that there is no air in the system. Make sure that the thermostat opens and opens at the correct temp. Make sure that the bypass system is functioning properly. Also, make sure that the pump is functioning properly.

Air flow is important for heat transfer – make sure that the radiator fins are not clogged externally. Make sure that the radiator is not blocked. Make sure that the thermostatically-controlled electric fan is functioning properly.

Coolant is important for heat absorption – make sure that the coolant is mixed in the proper ratio and that it is fresh.

A lean-burning engine will run hot – check ignition and fuel delivery.

A plugged exhaust system will make the engine run hot – check the muffler and catalytic converter for obstructions. Check the pipes for crushed areas. A non-functioning O2 sensor will lead to a clogged cat.
 

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Thermo/Radiator

Ron;

Thanks for you reply. Don't want to re-engineer my car, just queried about the thermo/bypass to get all possible solutions.
I've already ruled some responses.

-No leaks, cap is fine
-Radiator fins are clean and outside physical condition is good
-Cat and muffler and unobstructed
-No damage to exhaust system


Need to check:

-Thermo/bypass as you stated
-System probably needs flushing/recoring as I don't what the PO did and when

What about the O2 sensor? How can one tell if it has bad and needs to be replaced?

Thanks, Steve
 

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As yours is a 88, it should have a 3 wire sensor. Two for the heating element, one for the sensor proper. (usually green wire sorta by itself in a orange or yellow plug up by the brake master cylinder)

That heating element will help a bit, but you'll likely have to reve the engine to about 2000-2500 rpm and hold it for 30 seconds to a minute beofre the sesnor start putting out voltage. (if your heating element is good, revving won't be all that neccisary. If the heating element is bad, no real worries, as the sensor will still work once the exhaust temp brings it up to operating temperature with the revs, provided of course the sensor element is functional)

See section 12 of this page for a more in depth testign proceedure than I can explain here in less tha a billion words.
 

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Steve --

Sorry for the delay on this. The head gasket problem was not obvious, certainly. No chocolate soup in the radiator or oil pan or anything like that.

After reading some suggestions here on the BB, I checked the coolant reservoir by sticking my finger in it and definitely brought out the oily film from the surface. Then I pulled the dipstick and saw the oil beading up like water, because well, that's what was there (coolant, actually). So I figured I caught the gasket problem in the early stages, and an Alfa buddy here in town, as well as my mechanic confirmed. So I had the head pulled and re-done, valves ground and gasket replaced.

It runs great now, still needing an O2 sensor and maybe a cat converter. The temp still climbs slowly from 175, but has not been too seriously high, except on way hot days.

The only advice I would give is see if there's any mixture AT ALL of oil & coolant, regardless of appearance and take appropriate steps if there is. Prolong use with water in the crankcase can be especially damaging to the bearings, from what others on the BB have noted.
 
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