2004 VP 5.0GL-E SX-M 1.6 overheat in lake - not in driveway on garden hose attachment

[MNBrent]

2004 Glastron GX205SF with VP 5.0GL-E SX-M 1.6. Love this boat!!

New boat this earlier year. Bought in Feb and couldn't lake test it. Shame on me! Got it for a fair price. Boat has low usage and it shows everywhere, except the lower unit. Was stored outside last winter and rain-ice developed in the mounting bolt recesses of the sterndrive to transom shield, and apparently it cracked the housing. Previous owner had the upper gearhousing welded at a reputable shop in Duluth Mn., at the middle mounting bolt point on the right-hand side of the lower unit to transom. See attached pic.

Said he had it pressure vacuum tested, the lower units shifts and drives beautifully and the gear lube is VERY clean, not milky. Left side is perfect and unaffected.

Problem is it overheats when above 1400RPM. I can keep it cool while at idle and up to about 1400rpm. after that, the temp will rise quite quickly and I will have to drop the throttle back to 1400rpm to cool it off.

I replace the thermostat and the impeller. Original impeller looked great. Thermostat was slightly corroded. No change in overheat condition after this.

I did the clear tubes test set-up on the impeller pump in/out lines and saw while on the garden hose engine attachment at idle, I had 100% full tubes of water and the boat will not overheat even running up to 3000RPM. I removed the garden hose, closed the blue cap tightly, and put the lower unit in a large tub, which covered it up past the water intake holes on lower gearcase. With this, I had much less water being pulled into the tubes and I could clearly see much less water coming out of the higher water exhaust ports near the transom.

I also looked inside the water inspection plate area of the upper gearhousing, and it was very clean and clear.

So I'm now removing the lower unit to check the O-ring at the transom shield. I will be checking the water hose and bulkhead fitting up in the transom shield also.

Question is, are there any other points of water intake sealing in the lower unit that I should be checking for?

B.

 

[Don S]

Re: 2004 VP 5.0GL-E SX-M 1.6 overheat in lake - not in driveway on garden hose attach

Read my reply to this thread http://forums.iboats.com/showthread.php?t=554564

If that grommet seal gets pushed out of the way or doesn't seal because it's old, you will overheat as soon as you get on plane and that portion of the drive is out of the water.

 

[MNBrent]

Re: 2004 VP 5.0GL-E SX-M 1.6 overheat in lake - not in driveway on garden hose attach

Don
Does that lower grommet seal water from gear oil? It looks like that whole area is internal to the gear oil case.

The hose that passes through has an upper seal on top of it also, for I assume the upper gearhousing to hose. Does that seal water from oil as well or do I misunderstand the drawing completely?

Also to separate the SX gearhousings, it seems there are only 6 bolts. Is it that easy to do I need special tooling?

 

[Don S]

Re: 2004 VP 5.0GL-E SX-M 1.6 overheat in lake - not in driveway on garden hose attach

All those seals do is prevent air leaks from the pickups, not in the gear lube cavity at all.
If you were using muffs and not the flush fitting on the engine, you wouldn't have any cooling either, http://forums.iboats.com/showthread.php?t=545485&page=2&p=3807248&viewfull=1#post3807248

If you separate the upper and lower, you will need to drain the gear lube first or you will have a mess on your hands. You will also need the 2 orings for the oil passages.
Here is the manual for that drive. http://www.4shared.com/file/50982625/e2bdb42c/SX_DP-S_Service_Manual.html

 

[MNBrent]

Re: 2004 VP 5.0GL-E SX-M 1.6 overheat in lake - not in driveway on garden hose attach

Don
Thanks for that explanation on those two O-rings. I see that in the VP drawing and it now makes better sense to me!! I've seen the manual also for the teardown and just wasn't sure about any gotcha's involved with separating the upper/lower gearhousings. I want to avoid that if possible.

I'm hoping to pull the sterndrive, figure a way to perform a vacuum test on the water passage, possibly with electrical tape on both ends and my trusty mityvac pump, to see if there is a leak up to the transom O-ring seal area. Seems easy on paper.

 

[MNBrent]

Re: 2004 VP 5.0GL-E SX-M 1.6 overheat in lake - not in driveway on garden hose attach

I did pull the sterndrive and everything seems to look great inside of it and through the water intake passage. No damage to be seen at all. I tried the vacuum test on it with electrical tape sealing both ends of the water passage of the lower unit, but my little Mityvac hand pump didn't pull any vacuum. Not sure if the pump is too small, if my electrical tape seal for the upper gearcase to my Mityvac pump fitting leaked, or if my lower unit actually has a leak in the grommet and tube seal between the upper/lower halfs. I have the seal kit to replace this if I need to go there.

I did find the nipple fitting (VP#3852533) fitting going through the transom had a nut that was slightly loose and an O-ring which may be designed to seal that back side to the pivot housing. This was leaking air tremendously through a weephole that is drilled into it. I sealed this up with 100% silicone and put everything together. I assume this weephole is to pull any water that could become trapped at the pivot housing bulkhead hole that this fitting goes through. I put everything back together and now I was pulling as much water through the exhaust with the lower unit in a tub as I did with the engine flush attachment hooked to a garden hose. So I thought I was good to go and we went to the lake.

We'll same story, she overheats at idle and over 1500 RPMs, but just seems to take a little longer to do it and seems to cool faster.

Out of frustration, I shotgunned the complete seawater impeller pump (VP#21214596) as my original had the plastic tubes on it, and I was planning to replace it eventually either way. I'm going to test it again ASAP in the driveway in a tub to see if there is any improvement.

My random thought is its almost acting like the circulation water pump on the front of the motor is not pushing fluid through the block when the thermostat is open, and is relying on the small amount of impeller pressure to move any fluid through the block, resulting in a much lower rate of heat transfer out of the block.

 

[Don S]

Re: 2004 VP 5.0GL-E SX-M 1.6 overheat in lake - not in driveway on garden hose attach

Maybe this will help http://www.4shared.com/file/50572185/e88f1d89/Volvo_Penta_Overheat_Diagnosis.html

It's the first item in the Volvo section of the stickies at the top of the forum.

 

[MNBrent]

Re: 2004 VP 5.0GL-E SX-M 1.6 overheat in lake - not in driveway on garden hose attach

Found the problem. I used an electric vacuum pump from work and electrical tape to seal off areas to test the inlet cooling system. I divided things up until I found the section that would not allow any vacuum to be developed.

I kept a log of everything I did and was up to step 16 by the time I got smarter and used the vacuum pump:

16)Vacuum pump coolant passage inlet testing
SET-UP:
(A)black electrical tape put over all water intake ports and the lone single port on left hand side of lower unit
(B)1 inch pvc sch 40 pipe to 3/8 coolant hose with duct tape holding them together
1-full system from impeller pump inlet hose to lower unit water inlet ports fails the vacuum test with 0 vacuum generated with electric vacuum pump
2-half system test from impeller pump inlet hose to transom shield nipple fitting passes the vacuum test with 20in hg and holds
3-half system test from lower unit transom shield sealing surface to water inlets ports fails the vacuum test with 0 vacuum generated with electric vacuum pump
4-half test from impeller pump inlet hose to lower unit top gear housing section tube outlet. passes with 12 in hg generated. As soon as the This tests the upper gear housing

17)Dismantle lower unit upper and lower gear case housings
Bought VP 3855275 seal kit and 3 qts VP synthetic gear oil 75W-90 for gear case
A-drain oil
B-mounted onto transom shield and take out 6 bolts holding housing together.

*Hose lower gasket grommet VP#3854595 was pushed up onto the tube and not making a seal to the lower unit. It was improperly positioned and did not seat into the lower gearcase housing, causing a massive air leak* SMOKING GUN!!

18) Vacuum test upper gear housing of lower unit
1-half test from impeller pump inlet hose to lower unit top gear housing section tube outlet. Passes with 12 in hg generated. As soon as the vacuum is stopped though, it releases and goes to atmosphere. This tests the upper gear housing for any cracks and appears to look good.

19) Vacuum test entire system
SET-UP:
(A)black electrical tape put over all water intake ports and the lone sinlge port on left hand side of lower unit
(B)1 inch pvc sch 40 pipe to 3/8 coolant hose with duct tape holding them together
1-full system from impeller pump inlet hose to lower unit water inlet ports passes the vacuum test with 17in hg developed maximum with electric vacuum pump.

Vacuum and Pressure tested the gearcase and it passes both tests pretty nicely. Friend borrowed me the tools.

20)Water test in driveway
1-set-up engine on engine flush to prime the impeller and bring the motor up to 160degrees. No overheat occurs on engine flush attachment with pressurized garden hose.
2-tested with large bucket of water and only lower unit water pull from water inlet ports and no overheat occurs with 2K and 3K engine speeds or at idle. Engine stays at 160degree temp.

Lake tested the boat and it stays right at 160 degrees for 5 full hours of high speed boating!!!

Happy camper.

 

[Tail_Gunner]

Re: 2004 VP 5.0GL-E SX-M 1.6 overheat in lake - not in driveway on garden hose attach

Geesh that looked like a no brainer... Thanks for the tip good work.

 

[vwbugman69]

Re: 2004 VP 5.0GL-E SX-M 1.6 overheat in lake - not in driveway on garden hose attach

What pump did you use to do your testing? I will be going down a similar journey soon.