GL1200 overheating

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mcgovern61

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Location
Kingsport, Tennessee
My Bike Models
Former '82 GL1100 "The Slug"
Dan, I know that you have been pretty busy getting the board up, but some of us are still hanging on whether you figured out why the 1200 was running hot and getting air.
 
No, I havent figgered it out yet.

It's been on my list to get back into it, probably next weekend I'll have more time but in the meantime any other ideas are welcome.
I'll post everything I've done to refresh memories, including mine :mrgreen:

In the meantime I've been working on incorporating a photo gallery into the forum, I really want to get this working, it'll be sweet!
 
And the videos that were posted on that thread are gone, too... :sensored: :sensored:
Perhaps they could be reposted...wink-wink-nudge-nudge... :mrgreen: :laptop:
 
Here is my video of running the water pump on the starter. It is a video that shows that at least the older original water pumps do move water even when just on the starter. One of the potential issues with the 1200 in question was that there did not appear to be water moving through the engine.

[video]https://www.youtube.com/watch?v=OD9QDznVsRI[/video]

(added youtube code AApple)
 
Here they are :mrgreen:
[video]https://www.youtube.com/watch?v=uS46BN6bNVc[/video]
[video]https://www.youtube.com/watch?v=G_BkaQP722c[/video]

And another video of his for good measure :grin:
[video]https://www.youtube.com/watch?v=V7-Fzfwn6_E[/video]
 
mcgovern61":1vs5dssk said:
Big Andrew, how do you copy and paste a youtube video like that? I can only paste a link.

You gotta add [video] to the front of the link and then add [/video] to the end of the link
 
Ok, time to get back to this and get it sorted out.

Some history of the problem.

The owner has put on 30k miles. The temp has always run in the 3/4 scale.
Sometimes pulling hills in 90 plus temps it will not overheat but down on the flats temp will get to the red line.
Parked and hot it would bubble like it's boiling over.

Repairs I've done.

1. New and tested Tstat.
2. New water pump.
3. Replaced both head gaskets with Honda brand.
4. Tested temp gauge, scale is accurate.
5. Both heads machined flat, decks are flat. Heads were not pressure tested.
6. Radiator rodded.

What happens now when riding around town is the temp will climb to 1/2-3/4 scale, the fan will come on and stay on longer than it should. The temp will drop slowly.
When running 60-70 mph the temp will climb slowly past 3/4, fan running steady, and it will approach the red zone.
I've tried with and without the Tstat in.

When the engine is running and rad cap off, what happens is what you see in the videos.
It acts like combustion entering the cooling system so I've done a few tests to try and figure out which side before tearing it down. This is pretty much where I'm stuck.

I've done a leakdown test with 140 lbs at each plug hole for at least 5 mins with the engine warm. No bubbles appear in the radiator.
So....then I ran the engine to full operating temp with each side's spark plugs removed to relieve compression on that side. Still get bubbles into the radiator with either sides plugs removed. :?: (strange)

I've pressurized the cooling system to 25 lbs with the engine hot, no coolant appears to be entering any of the cylinders.

Because of these tests we started wondering if the problem was not combustion gases, rather a coolant flow problem so as the videos show it looks like there could be a problem here but I need to test and compare some more.

I've compared a new 1100 pump I have. Measured every dimension and they are identical.
The front pump cover is slightly different in design so I installed that. It does seem to have made a slight difference in flow when cranking so I put it back together.
The bubbles still come up like in the video.

Frustrated as hell, I think I need to pick up the test kit to check for exhaust gas in the coolant so I know which way to keep looking.
 
Checking for exhaust gasses made be needed, but there is one other cheap flow test that can be done.

Remove the antifreeze and both hoses and install 1 high temp rated clear hose from the engine to the pump and bypass the radiator. (Clear high temp hose available at West Marine or other marine or boating retail stores.)

Cut the hose near the top and install a tee with another short piece of hose (about 10" high pointing up from the tee) that will be used to purge the air while filling and running. (Same function as an expansion tank) Very slowly, put water only back into the engine thru the tee while running the engine at idle. Fill the engine until there is about 1" of water up in the tee. (Only run until you are sure the system is full of water and no air, but the engine should not get warmed yet.) Let the engine sit a few minutes after you are sure the air is out.

Run engine to temp and observe the flow when the tstat opens.

Check to see if the air bubble shows up and observe the water flow. Even if the bubble shows up, continue to run to check water flow from the pump. The tee should allow air to be purged as the system is running. Add water to the tee if needed to keep it at 1". This checks both the pump flow and whether combustion air is making it into the closed system.

If everything works fine, add the radiator back in using the clear hose again and try the same test to see if the radiator is causing a problem.
 
A cooling system is just a simple equation. How much heat gets put into it and how much heat can it remove. Based on the work you've done and the tests you have run It doesn't sound like you have an exhaust leak into the cooling system.

So either the cooling system can't cool it, or it is just generating too much heat.

The bubbling of the coolant looked normal to me until you said it that the video was shot with the thermostat removed. That is exactly how mine looked when I tried to let it warm up with the thermostat installed, so that I could top off the coolant. I let it run with the cap off and it just bubbled up over the top of the filler tube and made a smoky stinky mess. But on your bike it should not do that with no thermostat installed. That is the biggest clue that you have. It doesn't beahve like it should with no thermostat installed. I still think there is something wrong with the flow of water in that engine. That's why I suggested the test of the pump. If you have the bike running and you can visually see that the water is circulating well, then I think you can rule out the pump.

I still think it is flow related, but let's consider that maybe it isn't?

You have already investigated the leakage of exhaust gas, with negative results.

What else would cause an engine to overheat? There are two sources of heat in an engine. One is combustion, but teh other is friction. I had a 1070 VW Beetle that overheated. I never knew why, until I tore down the engine to rebuild it. The casting was flawed at the no 2 main crank journal. This caused a lack of oil flow and pressure to the no 2 main bearing . This burned and spun the bearing, but it also generated enough friction that the engine overheated.

Is it possible that you may actually have a lubrication problem? Have you tested the oil pressure or flow rate, if there is a way to do that? I've heard of people using too much of an oversized replacement bearings.

Often times when I am stuck on a problem at work, it is because I am looking at the wrong place for the solution. Maybe that is what is going on here as well?

Good luck,

Dennis
 
Were the heads warped and needed machineing if so theres no dought that its been real hot. one way are another you need to see the water pump work, id take the thermostat out and check to see that pump is moving water through the system. ive never had pump problems what ever drives it needs to be checked i dont think its moving water. when you get it figure out you need to toss that termastat, being its been hot enough to warp the heads it is even more susceptible to failure from fluctuating temps than before. put in manual switch for in town traffic, mine runs cooler in traffic with switch on than any other time. point being the motor runs more consistance temps without going up and down all the time with heads that have already moved. hope nothing big going on and you can work it out joedrum
 
Well I went ahead and picked up a tester known as "block check" which tests for combustion gases in the coolant.
The idea is if it tests positive for combustion gases in the coolant then you kill cylinders by removing plug wires then retest until it comes up negative. This tells you which cylinder, or pair of cylinders in the case of our flat four cylinder.

It uses a blue liquid filled to a fill line.
As you squeeze and release the bulb it sucks air in, in this case combustion gasses would get sucked in thru the blue liquid which makes it change color slowly from blue then green then yellow.


[video]https://www.youtube.com/watch?v=NHt1guPR1Ic[/video]

I ran the test with all cylinders firing, the fluid turned green once the engine was completely warmed up.
Then I started over with fresh liquid after pulling the plug wires from one side and ran again.
I kept running it as long as I could but then coolant got sucked in and ruined the test, It didn't seem like it turned color until coolant got sucked in telling me there were NO exhaust gases present (yet)

I need to run this test a few more times, I'm not sure what I'm seeing just yet because I have to make sure it didnt suck in coolant the first time when all plugs were firing. I'm not sure how I'm going to get a accurate test because once the engine temp gets to around mid gauge coolant bubbles up the filler neck and gets sucked into the tester voiding the test. Even if I drain the coolant down it still bubbles up. I dont want to drain too far down so there isnt coolant flowing.

Argh!
 
I still think your pump ain't pumpin'. Your original radiator cap off video looked exactly how mine acted before the thermostat opened up.

However, I was looking at reasons for an engine to overheat. One of the reason listed was a blocked exhaust system. I had a catalytic converter that became plugged and the temp gauge used to shoot up like a rocket. Is it possible your baffles are too full of soot in the mufflers? I don't know if the 1200 has the exhaust in 1 piece like the 1100 or if it is in 2 parts like the 1000, but is there any way you can check the exhaust, maybe remove the baffles? It's just something no one has mentioned before as a possible cause of this problem.

The other issue was the air pocket problem. I've heard of that on Goldwings from one of the websites, probably the naked goldwing site.

That's a pretty cool tester you got there. Could you possibly test it at the overflow reservoir? Just cover the lower radiator cap to make it airtight with a flat piece of metal or wood. Not with a radiator cap which would require pressure to vent to the overflow. Just a flat piece of something, or even a plastic bag sealed arounf the radiator neck. Then if it boils over it would just go into the overflow tank, and wouldn't go into your tester.

Good luck, keep hammering on it. Eventually you will find it and everybody will say, "Well of course that was the problem! What was so hard about that?"

Take care,

Dennis
 
Could you possibly test it at the overflow reservoir? Just cover the lower radiator cap to make it airtight with a flat piece of metal or wood. Not with a radiator cap which would require pressure to vent to the overflow. Just a flat piece of something, or even a plastic bag sealed arounf the radiator neck. Then if it boils over it would just go into the overflow tank, and wouldn't go into your tester.

Excellent idea! I'll try that Sunday when I get back on it.
 
I had some time today so I redid the test by taping the radiator filler neck closed and putting the tester on the reservoir. That worked like a charm by the way.

Once the engine is at about mid gauge or alittle more I get a continuous flow of air into the reservoir and the test fluid turns yellow almost immediately indicating exhaust gas. It does the same thing whether right plugs are disconnected or left :cry:
I blew air into the reservoir between tests to be sure there was no residual exhaust gas in it.

Damn!

So......I guess I pull the heads and have them pressure tested. Dunno what else to try.
Since this has a sidecar in the way I'll do the left head first, put it back together and retest before doing the right.
 
dan filipi":2447olic said:
Once the engine is at about mid gauge or alittle more I get a continuous flow of air into the reservoir and the test fluid turns yellow almost immediately indicating exhaust gas. It does the same thing whether right plugs are disconnected or left :cry:

The exhaust gas showing up after the engine gets hot points to a potential crack in the block that shows up after the metal expands. That would explain why coolant does not show up in the oil.

I agree with joedrum, it appears that the engine must have gotten real hot at some point.

It is showing exhaust gasses when either side plugs are pulled indicates that the gasses are coming from the back side of the pistons (inside the case). :Awe:
 
It is showing exhaust gasses when either side plugs are pulled indicates that the gasses are coming from the back side of the pistons (inside the case).

hmm, can you elaborate on that some more? I'm all ears!
 
Exhaust gasses always bypass the rings even in small quantities (hence the reason for PCV valves and other crank case relief systems). Since you are seeing exhaust gasses regardless of which plug is pulled than the gasses are coming from the crankcase where all 4 pistons are dumping small amounts of gas. As the engine heats up, the crack expands allowing gas to enter the cooling system, usually around the piston liners. (Again, the crankcase side of the equation)

When the engine cools, the crack closes and water doesn't leak. You can try to pressure test for these cracks, but they do not usually show up unless the engine is at temperature. Dye penetrant is the only way I know how to find them and that requires engine disassembly.

We have run diesels engines with cracked blocks or liners for quite a while, but there is always the risk of the crack expanding and destroying the engine.
 
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