Overheating KAD32

Hi Peanuts - yep one of my earlier tests last year was running without thermostats and the problem still persisted. We think it may be a cracked head on the input side of the engine which manifests itself when the supercharger is run and hence where i have the problems at low revs. I have a new test to try to see if this is the case. I'm going to run the leak detection test, which came up showing no problems on previous tests this time when feeding the exhaust of a two stroke motor into the air intake whilst the supercharger is running. If comes up co2 on test it will be a cracked head, if not then back to drawing board but with another possibility ticked off. Enjoy your hols !
 
Overheating of over pressurisation

Ok - have I been barking up the wrong tree ?

Today I have run the test of feeding in the exhaust from a 2 stroke engine into the air intake with the supercharge running and tried the leak detection test - nothing! (which in a way is good news in that it means that it is not the cylinder block.

What I have done though is to create a video to show the coolant. Full throttle you will see that the coolant soon dissapears in the system, bring back the throttle and we have a frothy fountain.

I unplugged the supercharger and the same results happen. I have taken out the thermostats and the same results happen.

http://www.youtube.com/watch?v=2dsGdYOP5V0
 
Just watched your video (as its more exciting than Britains got talent) have you got the stats in when you did the vid? as it looks like the flow return from the turbo is very fast, have you looked at the hose from the turbo to the header tank, sometimes they get squashed under the charger pipe.

I cant see bubbles in the water so its not head gasket, as you rev it the water dissapears into the block so id say the fresh water pumps ok, but it sucks very quick and will cause and airlock in the head, id try bleeding the cooling system making sure the bleed hoses are 100% clear, remove and blow down them to make sure.
 
Hi Volvo Paul - glad you liked the video, this was before I took out the stats. The same effect with them out to a slightly lesser effect. I took off the bleeder hose from the turbo and blew through - this seemed ok, also took off hose from header tank - all clear. The system has been bled in the past but I will blow this through. Are there two bleed hoses I thought there was only one ?
 
Sorry to butt in here, but are there bleeding points on a KAD32? The owners manual just states to slowly re-fill into the expansion tank after a drain.
 
Your video is so similar to cars we have in the garage with an air lock in the system. Once the air is bled out, the rise and fall of coolant remains stable. I assume there is a small bore bleed pipe that returns to the header tank. You say that pipe is clear, but I have known plastic tanks to have a metal sleeve in the hose connection that corrodes and stops the bleeding process when the hose is attached. May be worth checking.
 
From the video I note that when the flow is fastest it sucks air down into the system through the whirlpool vortex.
Unless the expansion tank was full (and that would defeat it's purpose) I can't see how you can break the cycle.
Does the flow on the other engine go as fast? - If it does I my observation is irrelevant, but it looks like an issue to me.
It seems that the water flow is simply too fast through the header tank. Is there a blockage elsewhere that could be forcing the flow through there instead of going some other route?
 
Hi Brian

The flow in the port side engine is far more sedate, imagine water flowing down a partially blocked plug hole and you are there abouts, a small vortex but definitely no air heading down the system.

The speed of the flow could be down to an airblock in the system, which would cause that initial quick drop in the level as the air cavity is compressed but a block does sounds likely. Have had the oil cooler and the heat exchanger out and acid cleaned.

If anyone does have any other suggestions for testing for blockages would be greatly appreciated.
 
Hi

Yes it can be used in your engine cooling system, I used it in my engines on their first coolant change, I ran them for several hours before draining and flushing. The stuff that came out of the freshwater drain hose resembled a walnut whip and it stayed like it in the bottom of the bucket. So the way I look at you have nothing to loose so go for it.
As always look forward to your reply
 
Overheating

Hi All

Today I flushed the coolant system with coolant flush and spend over an hour flushing through with water afterwards before filling up with antifreeze again.

I ran the engine in the marina for 1/2 hr and all seemed well

Then out on a sea trial. Both engines ran compatable on temperature. We spent over 1/2 hr putting the engines through their paces - they heated together and cooled together. Full throttle and the throttling back both engines same on temp. After 1/2 hr the temp in the starboard engine didnt drop as quick as the port engine however still ran well.

When full power the temp then dropped to match the port.

The level in the header stayed relatively constant but there was a bit of frothing.

We then headed back to Portsmouth - the temp still OK. Dropped to 10 knots speed, temp on port engine dropped, starboard didnt. Dropped to 8 knots and within seconds alarm rang out.

Checking the engine bay out had spilled about 3 litres of coolant into the bilge.

Frustration to say the least. Anyone wants to buy a one engined s34!
 
It was asked at the start of this thread if the engine is connected to a calorifier, but I cannot see a reply?
It looks like air in the system to me, from the video.
If connected to a calorifier, can you disconnect it, both sides shut off at the engine.
If no calorifier fitted, then this post will self delete after a while, being useless!
 
Thinking: airlock: The highest point on the freshwater side is the turbo.

Could there be some sort of constriction inside there or the turbo return pipe ?
There is a separate coolant drain at the base of it.

dv.
 
Hi FlowerPower - I managed to bleed, albeit a light trickle, out of the bottom of the turbo at the weekend. The coolant drain on the turbo is a nightmare to get to due to raw water pipes. There are two drain plugs - only managed to do one.
 
Having thought about this a bit, I can imagine a scenario that might explain what is happening:
Bear in mind that water is not compressible!

- Imagine if there was a restriction in the highest point of the FWC side, somewhere near the exhaust manifold / turbo.
- When you refill the cooling system, this high point never fills with coolant, it's just an air pocket.
- You rev the engine up, and the FWC pump is "pushing" against this restriction, compressing the air pocket. The water level in header tank drops.
- You slow down, FWC pump pushes a lot less, the air pocket expands again and pushes the coolant out of the header tank.

If it were me, I would have the turbo off and have a good look around - see if there's something blocking the return pipe from inside the turbo.

dv.
 
Hi FlowerPower

I'm with you on the concept, there is a breather out of the top of the turbo which feeds back air into the header tank, I have blown through this and appears clear. I will though look at removing the turbo and checking.

The other recommendation is to swap over the exhaust elbows between both engines.

I'm looking at signing up for a night school course soon on engine maintenance !!

Will check out and let you know.

This weekend I'm giving up on power and have accepted the offer of a weekend sailing instead. Yarmouth here I come

Thanks again

Paul
 
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