Coolant level in radiator? (1 Viewer)

[beatle_bayly]

Once you clear that blockage, make certain the nipple connected to the standpipe is the one connected to the radiator. I bought an 80 years ago and the owner had the hoses on the overflow tank cap backwards. It would dump hot fluid into the overflow but couldn't pull any back.

Also, if you have a small air leak anywhere (like a failing waterpump), you'll often see fluid flow to the overflow but not get sucked back.

 

[LongDuck]

- what he said. Any other place air can get into the system, it will. It's a lot easier to suck air back in than fluid through the overflow bottle.

Once your new overflow bottle cap is in place (*correctly), I'm betting you've solved it.

 

[Kernal]

I did just get the headgasket replaced less than a month ago and have a new radiator,

OK forgot about the new radiator, so wondering if the blockage could have been from HG sealer dumped into the system previously??

 

[Plains Cruiser]

I did just get the headgasket replaced less than a month ago and have a new radiator,

OK forgot about the new radiator, so wondering if the blockage could have been from HG sealer dumped into the system previously??

Ya, that might be it! I'll have the new cap and straw tomorrow so we'll see how it goes.

 

[Plains Cruiser]

Nothing changed after the new hose assembly and cap. Is the next step a pressure test to see where air is coming in?

 

[Kernal]

Can you describe what is happening now?

Did you fill the radiator and then overflow tank (to the full mark), then drive it??

And then what did you observe (while the engine was running, engine off but still hot, engine off but after it cooled down after the run)?

Have you discussed any of this with the shop that replaced the HG?

 

[Plains Cruiser]

I haven't contacted the shop yet but that is my next step after replacing those two components yesterday. I drove it for a bit yesterday and then this morning observed the overflow tank full and the radiator still below the overflow inlet/out:

I will say that the cap wasn't pressurized this time, which is always had been for at least 2-3 days after driving for as long as I've been checking the radiator (before and after the HG job).

 

[BILT4ME]

I haven't contacted the shop yet but that is my next step after replacing those two components yesterday. I drove it for a bit yesterday and then this morning observed the overflow tank full and the radiator still below the overflow inlet/out:

View attachment 3362928

View attachment 3362930

I will say that the cap wasn't pressurized this time, which is always had been for at least 2-3 days after driving for as long as I've been checking the radiator (before and after the HG job).

The first two places I would look are:
1) PHH for small drips or wetness.
2) O-rings on the aluminum bypass pipe just above the thermostat. I had a leak there that it took me two years to find because it would dry out after running it.

 

[-Spike-]

I will say that the cap wasn't pressurized this time, which is always had been for at least 2-3 days after driving for as long as I've been checking the radiator (before and after the HG job).

Normally the system should only be under pressure when it's hot. As it cools down, it should draw a vacuum, which is what pulls the coolant out of the overflow (expansion) tank back into the radiator, and that should insure that the radiator is always 100% full (as long as there is enough coolant in the overflow tank to fill it). So every time the system gets up to operating temp, it pushes any air and some coolant out into the overflow tank. Then, when the truck is shut down and it cools, it pulls coolant from the overflow tank back into the radiator. However, because it draws a vacuum, any leak anywhere in the system can allow air back into the system. That's what it sounds like could be happening to you. Yes, you could get a pressure test kit and see if you can find the leak that way.

It is strange that your system would be under pressure for days. That could indicate that the pressure is coming from something other than heat expansion. You might consider testing for combustion gasses in the coolant, as I believe someone suggested earlier.

 

[Cutrex]

Mine is an HDJ 80 of 1994, and I am extremely interested in this thread because my symptoms are exactly the same. I have changed the radiator, its cap and its input and output hoses for new OEM units.

Here are some (unproductive, so far) thoughts that may be of help:

- Headgasket issue is discarded because i) the radiator was tested for pressure building up with the engine running, and pressure kept stable; and ii) a simpler test consisting in searching for bubbles coming out of the extreme of the overfow tank sucking straw, submerged in a glass of clean water, while the engine is running, resulted negative.

- To additionally discard gas pressure build up being the cause, I did open the radiator cap very carefully, with the engine still hot, a few minutes after having stopped it. Of course, the coolant is to the top of the radiator because it is hot. Also, any accummulated combustion gas should escape from the radiator at this point. Then I put the cap back and wait several hours. Now, a sound refrigeration circuit should be able to create vacuum by cooling, and suck refrigerant back from the expansion tank to the radiator. It didn't.

- I start to think in the explanation of a leak in the refrigeration circuit. I will inspect the two candidates suggested above by BUILT4ME.

- I plan to put pressure in the refrigeration circuit by pumping air through a testing cap, then i) see whether the pressure maintains (no leak) or decreases (leak), and ii) spread soapy water all over the refrigeration hoses and watch for bubbles while the circuit is pressurized.

Further suggestions and opinions will be very welcome!

 

[Funner]

I think it is also possibly one of the smaller hoses under the intake, aka bypass hoses or PHH neighbor. Get truck to operating temp, have someone that wants you to live in the cab; rev motor to 2500 rpms and hold it there, climb under the truck with a flashlight and look up on the drivers side of the engine. The leak can be so fine it dries on the hot block without leaving a puddle and won’t leak at idle. This will leak a small amount of coolant, but will also be where the air gets drawn back into the cooling system.

 

[Plains Cruiser]

Would it be unreasonable that I request the shop who did the HG repair to comp the cost of the pressure test? I’ll be taking it back in shortly.

 

[Malleus]

It's free to ask them

 

[Dave 2000]

I agree that does look like gung from a head gasket failure, it could also be an attempt to stop a leak using a sealer of some kind?

I have had my 80 for around 12 - 13 years. If the coolant recovery system is working correctly and there are no leaks the level should be right at the bottom of the neck when cold.

I fitted a new off the shelf no name aluminium/plastic radiator when I purchased the 80, fitted it and used a green 50/50 antifreeze. I reckon it's been drained and refilled four or five times? I think there was once for thermostat as preventative maintenance, once for a water pump, and a couple of times getting the electric fan and overheat warning system fitted.

Since I started using the car a couple of weeks ago when I recovered my driving licence, I have seen a brown staining at the bottom of the expansion tank, not gunk but if dried out looks like a powdery rust? The car had only done about 20...ish miles in 22 months! No leaks in the present high temperatures, but if I venture out off road after summer I may replace the radiator as a precaution?

Regards

Dave

 

[Dave 2000]

Check your radiator cap, you would not be the first to find you only have a one way cap as opposed to the correct two way version.

Regards

Dave

 

[Funner]

I agree that does look like gung from a head gasket failure, it could also be an attempt to stop a leak using a sealer of some kind?

I have had my 80 for around 12 - 13 years. If the coolant recovery system is working correctly and there are no leaks the level should be right at the bottom of the neck when cold.

I fitted a new off the shelf no name aluminium/plastic radiator when I purchased the 80, fitted it and used a green 50/50 antifreeze. I reckon it's been drained and refilled four or five times? I think there was once for thermostat as preventative maintenance, once for a water pump, and a couple of times getting the electric fan and overheat warning system fitted.

Since I started using the car a couple of weeks ago when I recovered my driving licence, I have seen a brown staining at the bottom of the expansion tank, not gunk but if dried out looks like a powdery rust? The car had only done about 20...ish miles in 22 months! No leaks in the present high temperatures, but if I venture out off road after summer I may replace the radiator as a precaution?

Regards

Dave

I get that too. I attribute it to the occasional vacuum on the expansion overflow cap pulling in some dusty air over and over again each time the radiator pulls in coolant from the expansion tank into the cooling system.

 

[leonard_nemoy]

Would it be unreasonable that I request the shop who did the HG repair to comp the cost of the pressure test? I’ll be taking it back in shortly.

No, it is stupid simple and should only take 10 or 15 minutes.

 

[Funner]

Would it be unreasonable that I request the shop who did the HG repair to comp the cost of the pressure test? I’ll be taking it back in shortly.

It would be unreasonable for a reputable shop to refuse this. That said, did you read post #31 and have you checked this?

 

[LandLocked93]

I have had my 80 for around 12 - 13 years. If the coolant recovery system is working correctly and there are no leaks the level should be right at the bottom of the neck when cold.

This is what I see in mine on a regular basis.

Since I started using the car a couple of weeks ago when I recovered my driving licence, I have seen a brown staining at the bottom of the expansion tank, not gunk but if dried out looks like a powdery rust? The car had only done about 20...ish miles in 22 months! No leaks in the present high temperatures, but if I venture out off road after summer I may replace the radiator as a precaution?

This too is what I saw in my res tank immediately following a gentle soak/flush of the radiator and heater core to resolve a no heat condition from the dash vents. The substance collected at the bottom of the tank over about 8 mos or so, ~1000miles.
I cleaned out the res tank and it hasn't happened since. My best guess is that it was residual rust particles continuing to break free from the flush process. I did not put a magnet on it tho that would have been telling.
I also have heat from the dash core too, so seems it was a successful attempt.

 

[Plains Cruiser]

Shop did not find any leaks when doing the pressure test. He's going to fill the radiator up completely tomorrow, let it run for a couple hours, and see if any coolant goes between the overflow and radiator after cooling.