Rebuilt engine, problems....

I think I remember the Tech Tip

saying it was pretty important that the cap be 13 lbs.. Perhaps Chris Obert can weigh in? The caps they shipped me were 13 lbs.
 
Thinking on this trouble..

Here's how I understand the problem:
• The car warms up and runs a steady temp at idle
• On the highway the temp creeps up and won't come down

The only time I have had this problem is when I I first got my Bertone. Originally I though the Corsa kit was causing problems with airflow through the radiator. Some creative work with plastic panels ensured flow was directed to the front of the radiator. The problem was slightly improved but would still occur on longer drives.

My fans would work when they were supposed to, etc. The basic issue was one of flow. Poor flow could be one of several things; bad pump, loose belt, sticking stat, clogged radiator. A new radiator fixed the problem.

I think you also have a flow problem. Check your belt tension, but consider seriously that your 3 year old radiator is clogged. A flush chemical like an off-the-shelf product or a mixture of vinegar might be needed.

If it were me I'd remove the radiator and flush it off the car. With chemical assistance if need be. This would also make it easier to assess its condition. Someone suggested using a mechanic's mirror to look down the tank, good idea I think. It could also need cleaning, the radiator fins catch all manner of "lint"; grass seed, bugs and even soot from other cars' exhaust.

With the radiator out you can also flush the other parts of the system as well. I like to use hot water and so I hook a garden hose to the sink faucet with an adapter. When I did this on my Bertone, the amount of crud that came out was surprising. I can imagine there was a lot of sediment in the metal fore/aft pipes under the car.

Hope this helps.
 
It's kind of odd that the cooling system was fine before the new engine and the trouble developed right after the new engine was installed.


Keeping in mind the new engine, hypotherically it could be (not in any particular order)....

1. There is something wrong with the way the engine was assembled that is affecting the cooling system. Maybe something about the head gasket or water pump being wrong that is blocking or redirecting coolant flow in a way that's not right.

2. Incorrect, bad, or wrongly installed thermostat in new engine.

3. Accidentally reversed coolant hoses between the stat housing and the undercar piping, or between stat housing and heater or between stat housing and expansion tank.

4. The temp gage sending unit that was mounted to the new engine is the wrong one for the car, sending a signal that is being read by the temp gage on the instrument panel as too hot.

5. Air pockets.

6. Radiator now significantly clogged for some reason---maybe sediment stirred up when the system was opened.

I would say that #1 is a longshot; #2 should have been addressed with the new stat; #3 is still a possibility; #4 probably can be tested with the specs and a multimeter to read electrical values; #5 should have been worked out by now; #6 may require the rad to be pulled and cleaned and flow tested by a rad shop.
 
PaulieNoodlesX19 said:
saying it was pretty important that the cap be 13 lbs.. Perhaps Chris Obert can weigh in? The caps they shipped me were 13 lbs.
Click to expand...
The original cap Fiat used fits ONLY Fiat radiator necks and is not shared by any other manufacturers that I have been able to identify. If you order an X19 cap from me you will receive a cap that will be rated at 0.8 atmospheres, not 13 pounds. Some Fiat family applications use a lesser pressure rating, and there are numerous different styles of necks, and therefore caps.

But for an X it's 0.8 atmospheres.

Our reproduction X coolant tank uses an alloy neck I get from Jegs that is built to use a Stant cap, and for that neck we provide the 13 pound cap because that is the closest cap to the 0.8 atmosphere the system was designed to run at.

I would never suggest you use a 13 pound cap on any Fiat radiator or cooling system that has an original neck as you will find that because of the incorrect neck depth for the 13 pound cap you will actually be running at something like 17 PSI, I tested it years ago back when Mark Plaia worked for me and I don't remember exactly what it released at. Possibly he does?

Doesn't matter, it's too high.

Often when I have radiators rebuilt I will specify that the neck be changed to accept the Stant cap, as an example I do it with all pre recovery tank Fiats so I can use a catch tank. And then I use the appropriate rated cap.
 
Well, I forgot to add

that I do also have the repro coolant tank that Mark P. fitted the car with.

Having said that, with the new radiator, thermostat and cap, my car has never run cooler. Now I need to do the same for our '76.
 
The front fan...one or two speed?

Does the front fan have 1 or 2 speeds, or settings? I think I am jumping right to the jet engine speed fan.

I drove the TimeX home from work tonight about 50 minutes. It ram at 190 MOST of the time. By the time I got home the front fan was cranking, shut off engine, rear fan started right up.

I drove about 40-45 miles per hour street traffic.
 
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I think your car is an FI car....the rear fan only runs when the engine is off, it is intended to blow some ambient air onto the intake manifold area to cool the fuel rail that pipes fuel from the supply line to the injectors, the idea being to try to prevent fuel from boiling in the fuel rail which would result in a no hot-start condition.

This fan system is indirectly associated with the engine cooling system, in that if the engine itself is running hot it would of course generate more heat in the engine compartment which would of course be more likely to trip the temp sensor for the FI fan.
 
Sorry Vinnie...

It would appear that your mechanic only does what you ask, and doesn't work to find the problem for ya... even though this one is quite time consuming. I wish he was doing more of the troubleshooting as he can SEE what is happening, and you and us here, can't.

As far as the stat goes... A GOOD stat will keep the car running at the correct operating temp, regardless of outside temp ot turning on the heater. In other words, the TRICK of using the heater for additional cooling really doesn't work in a system that is operating correctly. If you turn on the heater, the stat should dip 4 or 5 degrees and then immediately start to climb again and maintain the correct operating temp.

In MY experience... I have found in a system that had a bad gasket and a stat that failed to CLOSE properly, that turning on the heater dropped the temp and it stayed dropped for some time, then started to get hotter and hotter until it overheated again.

Back to you... I can ONLY ASSUME now that the hoses are correct, your cap and stat are working properly, the system indeed HOLDS pressure be it 13 lbs or 17 lbs, (that doesn't matter when it comes to the overheating issue...)

I believe its time to drop the radiator.

Its a rather simple task, jack the car up on ONE side, or from the front and place on stands... drain the system by loosening a lower radiator hose... then loosen and remove both hoses from the pipes, undo two 13mm nuts (if I remember correctly) and pull it down. There is a two wire plug to the fan, but I don't remember if its easier to reach before or after the radiator is down.

For you, it may be best to take it to a reputable shop to flow test, test for leaks (should not be any) and then rod, clean, test and repaint. Get a cost estimate... then compare it to the cost of replacing it from Oberts or Matt, and the guarantees, etc.

What I did was... I used a gallon of liquid swimming pool acid (and the proper gear). I laid the radiator on its face on a concrete drive, POWER FLUSHED it with rags wrapped around a hose with "house" pressure. Then drained and filled with pool acid, and let it soak for about 30 minutes. Then I flushed it out again with the garden hose.

Appeared to work great...

Good luck, let us know what happens next...
 
One speed.

The front fan is one speed. A/C models have two fans, that run at the same time. Adding the second fan if yours only has one is easy. But a single fan should work if the system is otherwise working well.

You could even add a switched ground jumper for the fan relay, so that you can make the fan run at will. This probably won't help your situation.
 
pressure question

As I understand it...

Pressure helps to prevent boiling, so wouldn't having slightly higher pressure be a good thing? I understand that an increase in pressure stresses plastic/rubber parts, but what problems would an increase of 5-7 lbs do?

Just wondering
 
The concern is that if you use a higher pressure cap, the old parts will leak, split or otherwise fail. A marginal heater core or valve could easily fail with just a few psi more pressure. Hose clamps can leak as well.
 
Well ya know technically the car is not overheating. It is running at higher temps than it used to. At 225 it's probably pretty close to overheating.

It is not losing coolant, it is not "boiling over", it is not running rough in a way that would make you think it's overheating.

Vinnie did note a few posts back that after driving, he did loosen the expansion tank cap and coolant surged out, when no coolant or steam was coming out before he loosened it. That would lead me to belive that the cap was holding pressure in the system until he loosened it.
 
I think that what's being said is...

The cap not holding pressure is not his problem.

If a cap holds no (or low) pressure, then the coolant will boil at 212 (or some temp slightly higher if it is holding low pressure).

When coolant boils, it forms steam pockets inside the engine. Since the area where the steam pocket is is not in contact with coolant, it heats up. Since it is not in contact with coolant, it therefore cannot have the heat removed by coolant flow.

The idea behind a pressure cap (as I understand it) is to raise the boiling point of the coolant to avoid the formation of steam pockets.

So having a cap that holds 13 lbs of pressure (or 17) means that a bad cap is not the source of the cooling problem. But there definitely is a concern that if the cap (which is basically a safety valve) is rated too high, that other parts will fail.

Pete
 
Vinnie do you know someone with a noncontact thermometer gun?

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It might help to check the temperature gradient of the radiator to see if you can identify cooler spots that might indicate low flow and therefore clogging.

See the color diagrams about 1/4 of the way thru the following page: http://www.troubleshooters.com/tpromag/200210/200210.htm
 
I still think

the fan is wired backwards so it is blowing the wrong direction. Thats what happened on one of my X's and it took me forever to figure out why I was overheating all the time. Switched the wires and it was fine.
 
That'd be easy to check for...

Hold a piece of paper or saran wrap up to the front of the rad and make sure it gets sucked in and stuck to the rad, rather than blown off it.

Pete
 
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