Overheating with new rad

[AFLA 4]

Hi folks, hope you can help on this one...

 

My rad leaked a week ago losing some coolant. Topped it up and headed to the local rad shop.

(instead of entrusting it with my faithful Indy...)

 

:-(

 

They identified the leak quickly and this led to a replacement rad.

 

However, ever since, the temp has been on the high side of 90 while idling.

 

Previously, it would cycle between 88 and 98, with the fan cutting in properly for around 20 to 30 sec. Providing a nice and consistent graph.

 

Now, the fan comes on and the temp does not go below 92.5 unless I massage the pedal a bit.

High temp reached is around ~99 and at least once the high speed activated.

 

A few seconds after the low speed kicks in, the rad is cold to the touch. Yet the fan will stay on for more than 4 minutes until temp goes down (to 92.5 the lowest). Air from the fan is cold. Heater if operated will emit hot air. A/C on will stabilize consistently around 90 yet higher than before replacement.

 

Both upper and lower pipes are hot at this point.

 

At cruise, temp is good at just below 90.

 

Thermostat opens up within 5 to 10.

 

As I had another job with my Indy, he inspected it and sent me over to his recommended rad shop that are good experts with old and newer Alfas. They said it is either the rad or the stat and their bet is on the rad by reason that it was the only change. They also said root cause might be a missing or malfunctioning separator between the high and low pipes.

 

Both said pump is fine according to flow in coolant tank at idle.

 

Came this morning to the local rad shop requesting a replacement. They stated they can replace to an original Alfa rad which is considerably more costly (twice the price) or replace the stat which they reckon is the culprit.

 

My indy offered to replace the stat himself and prove them wrong.

 

What do you think based on the symptoms? Can it be I have a faulty partially closed stat that was masked?

 

This is driving me nuts and I can't forgive myself not going to my trusted Indy...

 

 

Thanks for the help!

 

Afla

[Smaky 73]

I'd be surprised if you didn't have an airlock, open the bleed screws in the rad and in the pipe under the throttle body till the coolant flows smoothly.

 

Failing that you may have blown the head gasket.

[AFLA 4]

Thanks Smaky for your quick reply!

 

Already drove some 200 miles by now and did a bleed routine warming the engine with cap off. Upper pipe is kind of solid only momentarily during warmup but is fairly squeezable when hot. Also let some fluid go from valve on rad. Will retry in morning. Didn't know we have another below the throttle body. How is this one accessible?

 

Paraflu is clear blue and oil is clear w no mayo. I understand if gasket is busted would have the entire tank either fizzing with exhaust or swimming in mayo.

 

At the garage, the other issue was sump plug dripping from previous service a week before. After threading and new plug, oil was reintroduced as was new really. Looked as beautiful as 10w-60 can be so I reckons is not harmed.

 

Can gasket failure manifest differently?

[Smaky 73]

Yes, they most certainly can, some show as just small coolant loss over time, some blow between cylinders and don't interfere with coolant or oil, there's so many possible symptoms but only the common signs ever get mentioned, and then even mayo in the cap isn't a garentee of a failedhead gasket as in a low use engine through the winter it will form naturally from condensation in the air drwan through the air filter and circulating through the breathers.

[AFLA 4]

Hi Smaky,

 

Took it to my Indy and he concludes there is no gasket failure on account of checking the exhaust gasses, coolant and oil. We ran her for more than two hours in the garage. Have also ran her for around 1000 Km since replacement. The pump works fine and there is a nice flow back to the expansion tank from the engine at idle.

 

Also replaced the thermostat for a new one just to eliminate. The old Behr one was fine after inspection. Same phenomenon: first speed fan comes on and takes a few minutes to cool her down. The rad is cold to the touch after heat dissipated, yet the measured temp is around 95. Once I give it some gas, the temp drops. She doesn't warm much over this.

 

I will take it again to the rad shop to see what they can make of it and if I can get them to replace the rad for another model or another example.

 

I must say I don't think this is really overheating. it actually behaves ok in traffic jams, maintaining temp just above 90 or so. I guess this is due to the amount of cold coolant kept in the rad and the constant but slow movement.

[Smaky 73]

When it's warmed up, does the top hose go rigid?

[AFLA 4]

Only before stat opens it is fairly rigid but can still pinch through with force and move some coolant. Once opened and really hot so you cannot hold for more than a couple of seconds, is flexible and can squeeZe all the way through moving larger amounts of coolant.

[Smaky 73]

OK you have air trapped, top up the header tank to the MAX mark and then unscrew the temp sensor from the t'stat, when coolant flows bubble free tighten up the sensor again and top up the coolant.

[AFLA 4]

Hi Smaky,

 

I have bled the system more than once by now and covered more than 1000 Km yet the symptoms do not change.

 

I consulted with another ex 156 owner that experienced the same phenomenon. He eventually got it solved by his rad shop expert that closed a baffle on the right side tank, where both pipes lead to. It seems either there is no baffle plate to begin with, or the baffle is faulty.

 

Another reason I think this might be the case, is that I hear that for certain rads, the baffle might contain a hole by design. I understand this has to do with enabling flow even while the rad is stuck or frozen (for sub zero climates?).

 

Have you heard of this failure before? Or of this design?

 

The rad itself is by Ordonez, but I found that the manufacturers part no. is 206601361 - for which I didn't find anything in Ordonez catalogue online. Can it be just the wrong one for me? The dimensions are the same and it's an aluminum rad.

 

Thanks again,

 

Tuval

[AFLA 4]

Oh, and just to add - I have not overheated really since and the temp does go down eventually. It's just that I am used to it going down really quick after the fan is started and the rad is cold to the touch.

 

Heater blowing hot from start even when engine cold btw...

[Smaky 73]

Hi Smaky,

 

I have bled the system more than once by now and covered more than 1000 Km yet the symptoms do not change.

 

I consulted with another ex 156 owner that experienced the same phenomenon. He eventually got it solved by his rad shop expert that closed a baffle on the right side tank, where both pipes lead to. It seems either there is no baffle plate to begin with, or the baffle is faulty.

 

Another reason I think this might be the case, is that I hear that for certain rads, the baffle might contain a hole by design. I understand this has to do with enabling flow even while the rad is stuck or frozen (for sub zero climates?).

 

Have you heard of this failure before? Or of this design?

 

The rad itself is by Ordonez, but I found that the manufacturers part no. is 206601361 - for which I didn't find anything in Ordonez catalogue online. Can it be just the wrong one for me? The dimensions are the same and it's an aluminum rad.

 

Thanks again,

 

Tuval

 

I'm aware of that design but it's not in use on these cars, so I'd say they are supplying the wrong style.

 

But the hose should never be really stiff to squeeze, it will firm up as the pressure increases with heat, alas that would be a symptom of a failing head gasket or simply a duff header tank cap.

[AFLA 4]

Just to set things straight - she runs beautifully now for over a month (Aside from my 4th gear skip issue that is). Also while hill climbing the Jerusalem mountains and traffic jams in Tel Aviv. Guess it really was an airlock after all. Plus the new thermostat improved MPG!

[Smaky 73]

TADAAAAA!!!