Heat exchanger repair .?????

[sledheadgeorge]

Last year at the end of the season some studs let go and damaged the heat exchanger. Got it repaired and installed a new track.
There are 3 welds approximately 3 inches long along with a couple of other 1 inch spots. System pressure tested and no leaks. Will these welds decrease the cooling capacity of the system. Never had an overheating issue before but now I do in all kinds of riding conditions and temperatures.
Coolent is testing fine. Oil is fine. Spark plugs are clean. No sign of head gasket failure to me.
This is got me baffled.
Any ideas?

 

[canoehead]

Pressure check carried out? How do you rule out "no sign of head gasket failure"? As long as the repairs are good you shouldn't have to worry about decreased cooling capacity. Did the welds fill or block the exchanger? I think you might to do a bleed down test.

 

[poor farmer/logger]

Guess it depends on how they welded it. Could possibly restrict flow if they welded the tubes inside shut. If it was just a external weld I don't see how it would restrict or block off flow.

Have you had it out and ran it yet? Does it overheat?

Ryan

 

[canoehead]

Guess it depends on how they welded it. Could possibly restrict flow if they welded the tubes inside shut. If it was just a external weld I don't see how it would restrict or block off flow.

Have you had it out and ran it yet? Does it overheat?

Ryan

I don't think they would need to externally weld it if it wasn't leaking?

 

[mattyg1405]

We'll I've repaired a few of my friends heat exchangers by welding and none lost any capacity in cooling or restriction, that being said does not mean that your could be welded through the tubes but even then I wouldn't think that would cause your overheat issue. If you pressure tested it you know it doesn't leak, start the process of elimination

 

[canoehead]

Guess I should ask how all of this was discovered in the first place. Did you get a overheat when riding. Perhaps tell us what happened from the start and how it was discovered..

 

[sledheadgeorge]

Guess I should ask how all of this was discovered in the first place. Did you get a overheat when riding. Perhaps tell us what happened from the start and hoinstalled uner s discovered..

Was riding at the end of the season last year when the engine temp warning light came on. Pulled over and saw antifreeze leaking. Got towed out and when I checked the heat exchanger was damaged. 3 big tears and couple other spots open. Got the heat exchanger welded I installed new track and when I went for a ride the temperature warning light came on again while riding. Seeing that it was the end of the season with warm temperatures I wrote the season off only because I had no studs in the track.
When I first got the machine I had experienced similar overheating until I installed some studs. Then I never had an issue till now. Have tried riding this week with new studs installed with mild moderate and very cold weather, with overheating results every ride.
Spark plugs are light brown and no sign of anti freeze.
Compression test across all 3 is at 140 to 150. Engine has 6000 miles.
Oil is fresh and clear.
Pressure test cooling system at 25psi for 1/2 hour and no drop of psi.
Thats why I asked if these welds could inhibit cooling performance.
Thanks for the feedback.

 

[mattyg1405]

I'd have to see a pic to see if the welds looked like they we're large enough to restrict flow... Do you have a pic .?

 

[poor farmer/logger]

canoehead, I don't think you understood what I was saying. Basically the same as what you said. You replied while I was replying too. Didn't see your post till now. Had a couple of things on the go while I was replying.

If they welded one or more of the tubes shut when they welded it, it could restric the flow. Try feeling the exchanger when the sled is first warming up and see if it's heating up evenly or if there's some cold spots on it. Should hopefully give you a clue as to weither or not they welded the tubes shut.

Ryan

 

[grizztracks]

Are these exchangers actually ported? I thought they are basically coolant reservoirs with an in and out. I've had several repaired with no issues with any restrictions. I know these engines tend to warp the head when overheated and then push antifreeze out the overflow.

 

[poor farmer/logger]

grizztracks, I can't say for sure. Always just assmumed they were. With the ribs in them is what made me think they were. Most every other heat exchanger I've worked on has but I've never had one out of a nytro. Hope to never have to too.

Ryan

 

[grizztracks]

The ribs on the exchanger just add more surface area for heat dissipation. These are very basic although they may have a couple baffles built in. They are nothing like two sided exchangers that use another fluid to carry away the heat.

 

[sledheadgeorge]

I'd have to see a pic to see if the welds looked like they we're large enough to restrict flow... Do you have a pic .?

Here is a picture of the welds. I have to check out the thermostat. Thats the only other thing that has not been checked out.

 

[sledheadgeorge]

Checked out the thermostat and its fine.Do you guys think that the welds have restricted the cooling capacity of the heat exchanger?

 

[canoehead]

Have you checked to see if your rad fan comes on? Has the system been bled fully? I'm not sure if the lower exchanger is a tank or core type. If it is a core type then it's possible it's plugged. Did you shut it down immediately when you had the overheat light? What about sender? I know I t's a long shot.