[Woody]

I've read the other posts on this issue, but something's come up that's a little different.

Ok, so the history. Driving one day, my fan gave out and shattered the shroud. Oddly, not the engine mounts...there's plenty of clearance...the fan just gave out. I was fortunate, no hood damage, no radiator damage...just fan and shroud. I should mention it's an 82 Spider.

No problem, ordered replacements from IAP and had my mechanic install. He also flushed my rad, cleaned it with a hose and installed a new rad cap.

Unfortunately, the car now runs around 212 at speed when it used to never go above 180-184.

Here's the interesting part. When are turn left, the temperature goes down...when I turn right, the temperature goes up. What's with that?

I haven't checked the thermostat or the sender unit yet, but wanted to diagnose this oddity before going forward.

Any ideas? Thanks, as always, to this incredible board for all the help I have received.

 

[Alfacliff]

the temp change with speed indicates an air bubble that moves around when you turn, try bleeding the system again.
cliff

 

[Fibonacci]

Mine Too!

Here's the interesting part. When are turn left, the temperature goes down...when I turn right, the temperature goes up. What's with that?

Any ideas? Thanks, as always, to this incredible board for all the help I have received.

Mine too! (1981)
I try to make more left turns if it is a hot day. What's odd is that it is a seemingly large movement, like + - near 10 degrees. More than just centrifugal force movement.....

I've always suspected faulty sensor, but perhaps there's some air left in the cooling system. I'll defer to the board consensus.

 

[Erik]

I've noticed that the electical connection to the sensor is important. My gauge had started to go to normal (80 degrees Celsius) and then suddently drop to around 60. Later it sometimes only when to 60, other times it went 80 and stayed or dropped.
1 or 2 weeks ago fidling with distributor the lead to the sesor fel off it connector. I fitted a new connector and since the gauge have performed with it useal imprecision, ei, showing around 80 again.
Erik

 

[Duke58]

From experience- sounds like an air bubble.

I thought my system was bled and had this problem. Don't be afraid that some coolant is going to get on your engine and/or on the ground like I was...

 

[papajam]

I've noticed that the electical connection to the sensor is important.

Yes, extremely important! Not just the connector to the sensor but the wire to the connector. The wires can fray and loosen in the connector causing poor contact. Also check to see if the HT leads are in close proximity of the sensor wire.

 

[GTV4EVR]

Jim,
What is the affect of having HT leads close (or touching) the sender wire?
Thanks...
Ken

Yes, extremely important! Not just the connector to the sensor but the wire to the connector. The wires can fray and loosen in the connector causing poor contact. Also check to see if the HT leads are in close proximity of the sensor wire.

 

[Woody]

and, please excuse my ignorance, what are the HT leads?

 

[Alfacliff]

spark plug wires. current can inductively couple into wires that are too close.
cliff

 

[slyalfa]

just one more thing to toss up. the needle does not seem to be balenced. if you have the gage out rotate it and notice how much it moves. that might be some or all of what you are seeing?.

just a thought.

by the way was the thermostart replaced? if so did you get the type with the extra disk on the bottom?

if not do you have the plastic part that fits inside the bypass hose?

 

[Woody]

I haven't replaced the thermostat yet...but it may be the next step.

I drove home last night in 32 C weather, got stuck in traffic and the needle tipped 212. Got home, and a small pool (six inch diameter) of coolant formed under the driver's side of the engine.

It hasn't leaked before, so I'm assuming it's from the increased pressure.

I'll check the wires and the coolant...after that, it's the thermostat.

Thanks all, will let you know how it goes.

 

[thegarzacomplex]

same problem here

My fan exploded due to old saggy motor mounts. the car runs hotter than it used to and my needle swings the same way you described. At first i thought i had mounted the fan backwards, so i reversed it, but did not solve the problem. Tried bleeding to no avail may try switching fan around again and bleed some more.
i'll be interested to see what you come up with.

 

[Tifosi]

The fan should be installed so that it pulls air when the engine is rotating counter clockwise when looked at from the drivers seat/flywheel end.

You can see which way the blades should orientated in this picture from another thread. (blades shown in picture are clipped, but indicate the direction they face nicely)

 

[Woody]

Ok, so...

The rad leak has been soldered and the rad painted (looks nice actually).

Car ran for 90 minutes at idle, in the garage, and the needle held steady at about 182.

On the drive home, the needle hit about 205! And at a time when the temp was only about 22C.

Thermometer has been tested, and appears to work fine.

System has been bled more times than I can count...and mechanic is convinced there is no air in the system.

My temp needle still swings when I turn right and/or left.

So, I'm down two three things a) the thermometer is messed, despite testing, b) my temp sender is faulty (rad problems caused by increased pressure from new rad cap), or c) I have a head gasket leak (oh gawd).

One additional thing...when I got home and the car was around 205 there was no coolant in the overflow.

Help?

 

[Erik]

Have you had the temp sender renewed? If not, it's worth a try.
One thing thou, these instruments are not very precise, so a readout from an external temp meter to see the exact temp, is probably the best way to go first. Such instruments exist, you simply point them on where you want the readout from (radiator), and you get the figure on the meter.
Erik

 

[Alfacliff]

with the engine hot, the overflow tank should have had more in it. as the engine cools, it pulls the coolant back out of the tank. did the tank smell of exhaust? a bad headgasket will cause this.
cliff

 

[GTV4EVR]

Woody,
How old is the sending unit? I find the newer sending units seem to read higher than the old ones. Every Alfa I've had ran with the pointer straight up. Both cars I have now (new thermostats and sending units) run over 200. I don't know the exact number but the needle points half way between half and max on the gauge. An infared temp reading off the thermostat reads about 195.

 

[Woody]

If I'm not mistaken, the sending unit is original. I'm going to get an external reading to see what the actual temp is.

The tank doesn't smell of exhaust at all, so hopefully not the head gasket.

Thanks again for the help.

 

[Woody]

Turns out the sender unit is providing a reading 15 to 17 degrees high. So, when running at 212, it is actually running 197 to 195. This seems to still be a little high, but out of the immediate danger zone.

Everything else seems solid...I'm about to put her to bed for the winter, so I'll decipher it in the spring.

Thanks all for your help.

Jeff

 

[rogerspeed]

I may have missed it, but no one has mentioned the fanbelt, they can slip at speeds above idle, the temp will be fine at idle, but under load on the road as it slips the waterpump doesn't circulate the coolant properly.