Temperature above 190.....

[tvmaster]

When you buy a "water pump", you are (with rare exceptions) not buying the entire pump. You are buying the impeller side only, as this is where the bearings and seals (the parts that wear out) are. You are reusing your old pump housing. You need both to measure clearance, so you need to check clearance with any new part that you buy. I bought a new water pump in 2013, and as delivered it gave me a clearance of 1.8 mm with my pump housing. I adjusted this down to 0.8 mm.

Your temperature gauge is showing a very believable 190°F under normal operation, climbing to a plausible 225°F (or thereabouts) during extended idling. A damaged cylinder head sender would not be on my list of things to suspect.

Both impeller and pump were replaced at the same time, in a combined unit purchased for “$130”. . Interestingly, the alternator was replaced four weeks ago, which is beside the pump. Any chance something was bumped, damaged during that event? What part of the engine gives the most accurate reading when pointing a thermometer at it?

 

[kmead]

Both impeller and pump were replaced at the same time, in a combined unit purchased for “$130”. . Interestingly, the alternator was replaced four weeks ago, which is beside the pump. Any chance something was bumped, damaged during that event? What part of the engine gives the most accurate reading when pointing a thermometer at it?

The outlet hose of the thermostat heading towards the radiator would be an easily pointed to and current reading of the outgoing temperature of coolant in the head. The sensor is bathed in coolant just upstream of there on the ’front’ side of the head.

You could also take readings along different parts of the head down near the junction of the head to the block, this is where the heat is generated. The cam box operates at a very different temperature due to being on top of the head itself and isn’t a good indicator of the heat in the engine itself (even though it is good and hot).

 

[tvmaster]

In our climate, where the car will never be driven below 50f, what’s best to fill the rad with, coolant, a mixture, or is water fine on it’s own? After reading this article this morning, I’m beginning to become more concerned, especially since EVERYTHING in the cooling system (save the two pipes) was replaced.
AKA “leaking head gasket“ mentioned in the article. Is this a problem that’s visually evident?

How to maintain your car’s cooling system - Hagerty Media

Overheating has provided plenty of fodder for black-and-white comedy films in days of yore but in reality, it’s no fun. Here’s how to avoid it.

www.hagerty.com

 

[tvmaster]

And while I’m checking things - the wiki service manual discusses the Water Temperature Gage Sending Unit (took me a while to find the GAUGE), but doesn’t really show a photo of it‘s location. Accessible from above or below?

 

[Dan Sarandrea (Phila)]

In our climate, where the car will never be driven below 50f, what’s best to fill the rad with, coolant, a mixture, or is water fine on it’s own? After reading this article this morning, I’m beginning to become more concerned, especially since EVERYTHING in the cooling system (save the two pipes) was replaced.
AKA “leaking head gasket“ mentioned in the article. Is this a problem that’s visually evident?

How to maintain your car’s cooling system - Hagerty Media

Overheating has provided plenty of fodder for black-and-white comedy films in days of yore but in reality, it’s no fun. Here’s how to avoid it.

www.hagerty.com

Standard 50/50 mix "Prestone" (the green stuff) is fine. Has the corrosion prevention you want, and has a higher boiling point than just plain water.

 

[Dan Sarandrea (Phila)]

And while I’m checking things - the wiki service manual discusses the Water Temperature Gage Sending Unit (took me a while to find the GAUGE), but doesn’t really show a photo of it‘s location. Accessible from above or below?

Here's a pic I borrowed from one of Jeff Stich's posts (as of this posting, this cyl head assy is still for sale at a very reasonable price!).

This is a cyl head from an FI car, but to my knowledge, FIAT never changed the location of the temp gage sender regardless of 1300/1500/carb/FI.

There are two "things" screwed into the head right above the #2 spark plug. The one with the brown Bosch connector is the thermotime switch which is exclusive to FI cars, The other one, with the single spade connector (green arrow) is the temp gage sender.

On my '86, the wire that comes from this sender has a brown boot, and the wire itself is IIRC green with a white stripe. No idea if that color scheme would apply to your '74.

 

[tvmaster]

Great find - thanks. One never knows, so I'm hoping it's one of these things and not a gasket going bad.
Here‘s how much fluid is left in the reservoir after yesterday’s liquid-hot eruption. Still too full?

 

[kmead]

Great find - thanks. One never knows, so I'm hoping it's one of these things and not a gasket going bad.
Here‘s how much fluid is left in the reservoir after yesterday’s liquid-hot eruption. Still too full?

View attachment 57104

If the line where ‘Empty’ represents the part of the tank which has no coolant in it ie air, then it is still a little over full but it will balance itself out. As Dan pointed out previously 2/3 full is about right, you are closer to 3/4. You may lose a bit more coolant but no big deal.

Always use distilled water mixed with anti-freeze which is a misnomer in that it actually raises the boiling point and lowers the freezing point. One of the most important parts of green coolant is the anti corrosion additives. These additives lose their protective quality over time so coolant needs to be replaced. Modern coolants, even the old green stuff, is good for five years. Some products like Water Wetter can be lifetime but require some extra work to make the transition, Hussein runs this product in his cars.

 

[tvmaster]

So I bled the system after running for a couple of minutes at 2k with the heater on max.
Air escaped, then fluid. Stopped there. Re-measured my tank wood, and it was down 50% from last measurement.
Checked Temp. Gage wire - seems connected.
Filled reservoir back up to 3/5 at most. Let’s see what happens now.
It‘s the fans not triggering until 230 that is my big concern.

 

[Dan Sarandrea (Phila)]

So I bled the system after running for a couple of minutes at 2k with the heater on max.
Air escaped, then fluid. Stopped there. Re-measured my tank wood, and it was down 50% from last measurement.
Checked Temp. Gage wire - seems connected.
Filled reservoir back up to 3/5 at most. Let’s see what happens now.
It‘s the fans not triggering until 230 that is my big concern.

Sounds like you burped out a fair amount of air, so I would call that progress.

After another burp session, let it cool overnight and then follow these steps:

1. Before starting, check expansion tank level to ensure it is the desired 3/5 to 2/3 full; add as needed. Replace cap normally. Slide heater temp slider to full cold.
2. Start up and warm up a bit.
3. Take it for a nice drive.
4. When you are 5-10 minutes away from arriving home, slide the heater temp slider to full hot.
5. Arrive home, park on level ground. Keep engine running.
6. Open frunk, remove targa if stowed, and have whatever tool you are using to open your bleeder screw/valve handy.
7. Place drain pan at front left corner under car, under the radiator bled screw, to catch any drippage from the next step.
***8. With engine running at idle normally, in one smooth motion, open the bleeder, count 1 Mississippi 2 Mississippi 3 Mississippi then close. Since you may not hear air escaping with a loud engine or in a garage, look in your drain pan. No coolant drippage means more air escaped; some coolant drippage means most air is out of the system.
***8a. Note: Time your bleed screw openings so as to not open the bleed screw when the fan(s) are running.
9. Do the 10 second 2500 rpm technique for two minutes, then repeat #8.
10. If you got only air in step 9, repeat once more. If you got some coolant drippage in step #9, stop here.
11. Switch off and allow to cool for a few hours.
12. Remove expansion tank cap and check level, if necessary adding to get to the usual 3/5 to 2/3 level.
13. You're done.

The above procedure should burp out the vast majority of air in the system, and should eliminate "excessive trapped air" as a reason for why your fans are not being activated at the correct temp.

***Edits/revisions.

If your fans do not operate as they should after the above burping sessions, then your next step is to either replace the fan switch with known good, or to remove the existing switch and test.

 

[tvmaster]

Ok, I think we’re getting some progress. While I’m only doing one burp today, here’s the result. I’ll continue Dan’s technique tomorrow.
Burp #1 results: Between idling and driving, got the temp to 190, and pulled halfway into the garage on level ground.
Between 190 & 200, the fans turned on. Woohoo. They continued to turn on and off for the next 7-10 minutes.
However, they didn’t keep the temperature at 200. Instead, it slowly kept creeping upward, to when I shut the engine down at. approx. 220.
But that’s progress over yesterday, and, no overflow left the tank.

Also, those fans sure take a bite out of the electrical system.

Honestly, everyone says the fans are loud, which they are, but if I wasn’t positioned nose-in the garage, and had the garage reverb, I wouldn’t have heard them turn on. Has anyone ever heard of wiring a spare, instrument cluster light to the fans? Or even a tiny red light mounted somewhere? It would offer some comfort.

Where I shut down today. Progress I hope.

 

[tvmaster]

Sounds like you burped out a fair amount of air, so I would call that progress.

After another burp session, let it cool overnight and then follow these steps:

1. Before starting, check expansion tank level to ensure it is the desired 3/5 to 2/3 full; add as needed. Replace cap normally. Slide heater temp slider to full cold.
2. Start up and warm up a bit.
3. Take it for a nice drive.
4. When you are 5-10 minutes away from arriving home, slide the heater temp slider to full hot.
5. Arrive home, park on level ground. Keep engine running.
6. Open frunk, remove targa if stowed, and have whatever tool you are using to open your bleeder screw/valve handy.
7. Place drain pan at front left corner under car, under the radiator bled screw, to catch any drippage from the next step.
8. With engine running at idle normally, in one smooth motion, open the bleeder, count 1-2-3, then close. You should hear the hiss of air escaping.
9. Do the 10 second 2500 rpm technique for two minutes, then repeat #8.
10. If you got only air in step 9, repeat once more. If you got some coolant drippage in step #9, stop here.
11. Switch off and allow to cool for a few hours.
12. Remove expansion tank cap and check level, if necessary adding to get to the usual 3/5 to 2/3 level.
13. You're done.

The above procedure should burp out the vast majority of air in the system, and should eliminate "excessive trapped air" as a reason for why your fans are not being activated at the correct temp.

If your fans do not operate as they should after the above burping sessions, then your next step is to either replace the fan switch with known good, or to remove the existing switch and test.

Between steps 8-11, is the tank cap left on?

 

[Dan Sarandrea (Phila)]

Between steps 8-11, is the tank cap left on?

Yes, the idea is to build some native pressure into the system from heat expansion of the coolant and any residual air, and then let that pressure help to force it out of the bleeder.

Basically you are just doing what Jay Leno's doing here:

 

[tvmaster]

"Always carry a fire extinguisher..." Italian cars...
As far as bleeding when it's warm - wear gloves before loosening the bleed screw, yes?

 

[Dan Sarandrea (Phila)]

"Always carry a fire extinguisher..." Italian cars...
As far as bleeding when it's warm - wear gloves before loosening the bleed screw, yes?

On our cars that fact that you need a tool of some sort to loosen the bleeder tends to keep your hand and fingers far enough away so that there's not really a significant scalding hazard. Not to mention that it is somewhat shielded by the sheet metal of the frunk, and the shape of the bleeder will send the fluid sideways and down rather than up. I don't use gloves when I do this.

 

[tvmaster]

Sounds like you burped out a fair amount of air, so I would call that progress.

After another burp session, let it cool overnight and then follow these steps:

1. Before starting, check expansion tank level to ensure it is the desired 3/5 to 2/3 full; add as needed. Replace cap normally. Slide heater temp slider to full cold.
2. Start up and warm up a bit.
3. Take it for a nice drive.
4. When you are 5-10 minutes away from arriving home, slide the heater temp slider to full hot.
5. Arrive home, park on level ground. Keep engine running.
6. Open frunk, remove targa if stowed, and have whatever tool you are using to open your bleeder screw/valve handy.
7. Place drain pan at front left corner under car, under the radiator bled screw, to catch any drippage from the next step.
8. With engine running at idle normally, in one smooth motion, open the bleeder, count 1-2-3, then close. You should hear the hiss of air escaping.
9. Do the 10 second 2500 rpm technique for two minutes, then repeat #8.
10. If you got only air in step 9, repeat once more. If you got some coolant drippage in step #9, stop here.
11. Switch off and allow to cool for a few hours.
12. Remove expansion tank cap and check level, if necessary adding to get to the usual 3/5 to 2/3 level.
13. You're done.

The above procedure should burp out the vast majority of air in the system, and should eliminate "excessive trapped air" as a reason for why your fans are not being activated at the correct temp.

If your fans do not operate as they should after the above burping sessions, then your next step is to either replace the fan switch with known good, or to remove the existing switch and test.

Well, if there was air coming out, I couldn’t hear it over the engine idling. Did it twice for good luck, and will wait until the next drive/idle to see if the fans kick in when they should.

 

[Datsun Guy]

If you get totally frustrated and think you still have air in the system, you could try a vacuum coolant filler. You drain the system, pull a vacuum, which removes the air, then let the vacuum suck in the antifreeze. Used one on mine after radiator replacement, no issues, runs right below 190 no matter the outside temperature. Tried to bleed, but only get fluid.

After reading this thread, I will lowered the level in the reservoir, it's almost full.

Btw, from earlier posts, the 190 degree temperature was chosen to reduce oxides of nitrogen, NOX. Never really saw any cars with that thermostat temp before 1974.
180 was the tried and true standard.
(Useless trivia, 160 for boat engines, as salt water crystalizes above that)

 

[Dr.Jeff]

Speaking of thermostat temp values, I've never felt comfortable running the higher temp units that a lot of cars came with. Some newer cars are above 220*. As was mentioned already it is mostly to reduce emissions, but at the cost of higher operating temp and - especially on older cars - increased risk of overheating and engine damage. In my opinion a T-stat of 180* is the max I'd ever consider if I lived in a cooler climate, 170* in a warmer climate, and in the outrageously hot desert here I even run a 160* T-stat in some of my vintage cars (actually they are more like 165* due to being German metric spec designed but are labeled as 160*). But keep in mind that the temperature rating of the T-stat is not necessarily the actual engine operating temp. There are a lot of factors that are involved in real world running temps and many vintage cars (particularly ones with compromised cooling system designs like the X) will run about 10-15* hotter (or more) than the T-stat rating. So my cars with a 160* T-stat operate normally around 175*, and can climb to 185* under some conditions. Much safer than starting at 190* and climbing to 210* or more. However I realize this can be one of those topics like choice of oils or spark plugs and everyone will have their personal opinions.

 

[fiatfactory]

The original thermostat for an X19 is 78 degrees C opening, the early 128 / 130 v6 also use an almost identical thermostat (Fiat p/n 4220309) which is an 82 degree C opening temp...the original 78C thermostat is no longer available whereas the 82 degree type is, and works just fine in an X19 as well... if 4 degrees C is making such a huge difference for you, then you have other issues afoot.

The X19 cooling system design is far from "compromised" ... what is usually compromised is the systems integrity from the use of non original parts, work done by previous mechanics and/or age related issues such as corrosion / blockages / incorrect impellor to housing clearance.

@tvmaster if the guys at WD did not do a head gasket retorque after the engine rebuild then the head gasket could well be pumping gases into the cooling system. The definitive check would be to pressure test the cooling system to ensure it's integrity.

and just a thought, I havent read the entire thread, but have you determined the cooling fans are in fact rotating in the correct direction and haven't simply been polarity reversed? they should be drawing air in thru the grille and ejecting it under the car.

If the alternator was recently replaced, have you checked the drive belt tension? it's amazing how much slippage can occur with an improperly tensioned drive belt

SteveC

 

[tvmaster]

The original thermostat for an X19 is 78 degrees C opening, the early 128 / 130 v6 also use an almost identical thermostat (Fiat p/n 4220309) which is an 82 degree C opening temp...the original 78C thermostat is no longer available whereas the 82 degree type is, and works just fine in an X19 as well... if 4 degrees C is making such a huge difference for you, then you have other issues afoot.

The X19 cooling system design is far from "compromised" ... what is usually compromised is the systems integrity from the use of non original parts, work done by previous mechanics and/or age related issues such as corrosion / blockages / incorrect impellor to housing clearance.

@tvmaster if the guys at WD did not do a head gasket retorque after the engine rebuild then the head gasket could well be pumping gases into the cooling system. The definitive check would be to pressure test the cooling system to ensure it's integrity.

and just a thought, I havent read the entire thread, but have you determined the cooling fans are in fact rotating in the correct direction and haven't simply been polarity reversed? they should be drawing air in thru the grille and ejecting it under the car.

If the alternator was recently replaced, have you checked the drive belt tension? it's amazing how much slippage can occur with an improperly tensioned drive belt

SteveC

Alternator was replaced by an old time X19 guy, who’s raced them for 30 years. But I’ll read up on how to check. Fans are sucking the correct way (lol), I’ll look into a pressure test though. Thanks.