2001 5.7 GI-A overheats

[efdog]

I had a fairly extensive overhaul late last summer/fall. New block, new thermostat, new manifolds and risers, new sea water pump to name a few things. Ran great last fall (just broken in with now about 10 hours). Before launching for the first time this year about a week ago I ran the engine for about 15 minutes on the flush hose. Thought it was odd that the thermostat didn't move.

Launched the boat last Sunday, and after about 10-15 mins the engine overheated. I killed it as soon as I heard the alarm...Checked the impeller just in case and it's still perfect.

Pulled the boat yesterday, hooked it back up to the hose and ran it for 45 mins without the temp gage moving at all. The engine gets warm, but not hot. Next I decided to try muffs, and after about 10-15 mins the temp starts to rapidly climb. As it approaches 190, I kill the engine. It doesn't seem like an appropriate amount of suction when hooked up to the muffs (a small amount of water coming from bellows area vs when I have it hooked up directly to the flush hose)...Air leak somewhere?

I've read through the overheat diagnostics. Way too awkward to do the clear hose test with the engine still in the boat. I've followed the hose from the pump to the drive housing area, and it appears good (no kinks). Hose outside the boat from housing to the drive also looks good visually (sorry as I'm not familiar with all of the correct terms).

Is it time to pull the drive?

I guess I just want some advise on next steps.

Cheers!

 

[Maclin]

Re: 2001 5.7 GI-A overheats

I apologize for the generalities and no details to follow as I am not as familiar with your exact drive, but what you describe is typical of a drive that feeds water up to an engine mounted pump.

There are plumbing components inside the drive to get the water from the intake grates up to the hose, it could be losing suction there. When the drive is submerged that is covered up at idling and slow speeds will not get into the overheat condition , then as the boat begins to lift at higher speeds the suction can be lost.

 

[Don S]

Re: 2001 5.7 GI-A overheats

This shows what Maclin is talking about.

http://forums.iboats.com/showthread.php?t=554588&p=3807255&viewfull=1#post3807255

 

[efdog]

Re: 2001 5.7 GI-A overheats

Thanks Don and Maclin

Looks like I'm removing the drive / lower unit apart to check out the seals. Are there any seals o-rings that must be replaced when I remove the lower unit from the drive?

To clarify, I overheat at idle.

I'll let you know my findings after taking off the drive.

 

[Don S]

Re: 2001 5.7 GI-A overheats

To clarify, I overheat at idle.
.

Then the drive is probably not the problem. I thought you were on plane.

How old is your impeller? Do the vanes straighten out in a few minutes if you take the impeller out of the housing?
You REALLY need to do the clear hose test, even if it is awkward.

 

[efdog]

Re: 2001 5.7 GI-A overheats

Impeller is OEM and was new with the sea water pump which was installed late last summer. It is still soft and flexible, however I didn't leave it out for 5 minutes to see if the veins would straighten. I did happen to take a picture of it

Ok, looks like I'm going to find the supplies to build clear hoses...thanks again

 

[Maclin]

Re: 2001 5.7 GI-A overheats

To clarify, I overheat at idle.

One more question please efdog, (now I feel like Columbo ),

You are overheating at idle in the water?

 

[efdog]

Re: 2001 5.7 GI-A overheats

One more question please efdog, (now I feel like Columbo ),

You are overheating at idle in the water?

Correct. Overheating in the water only. In the driveway with the hose attached to the flush mount, the engine wont actually even get to normal temp (160). I ran it for 45 mins and the temp gauge needle didn't move a bit.

 

[efdog]

Re: 2001 5.7 GI-A overheats

Sorry as this may seem like a dumb question, but I'm thinking about getting one of those massive rubbermaid tubs to use as a test tub, and I'm wondering if this is equivalent suction to running it in the river. It would actually be cheaper than driving back and forth to my nearest boat launch...Muffs don't seem like they would mimic the boat being in water at all.

Thanks!

 

[MNBrent]

Re: 2001 5.7 GI-A overheats

Muffs will supply pressurized water, and can mask a failure in the vacuum seal you need from the impeller pump inlet, through the transom shield hoses and fittings, and out to the sterndrive water intake holes. I can confirm this as I have the same overheat problem (2004 5.0GL-E with SX-M) and am going through it now. If I stick the muff TIGHT against the lower unit, I get all the water I need and don't overheat. On the lake however, I overheat at idle and somewhere near and above 2K rpms. 2K and higher RPMs and the temp climbs fast.

This is with 2 new impellers of correct part number, new thermostat, and sealing off the transom shield nipple fitting drilled port with 100% silicone, and new O-ring for lower unit to transom shield seal. I now have a completely new impeller pump just mounted this week that is 100% brass ($400 from local marine dealer)

My next test is to test the seals between the upper and lower sterndrive gear cases. I have a vacuum pump with gauges and will use electrical tape to seal off the water inlet tubes and attach my pump to the hose removed from the impeller water inlet. If I can pull a good vacuum, the seals should be good. If I cant, then I'm pulling the lower unit in half and replacing the tube seals. I already have the seal kit (VP#3855275).

 

[efdog]

Re: 2001 5.7 GI-A overheats

Thanks MNBrent. I've been following your thread as we have very similar issues going on here with the difference that I overheat quickly at idle rmps (7-800ish) when I'm in water. You're quite a few steps ahead of me. I just went to the hardware store today and got my clear hoses, pvc etc so I can see what is happening on the in / out of the pump. I've got a really tight engine compartment, so It's gonna be tough to actually get in there to add the couplers, and even tougher to actually stick my head down there to see what's happening with the engine running!
I picked up a big tub today, but it's not big enough. That DP is actually bigger than it looks! I'm gonna need one of those big deck box tubs I think.
Anyway, I'll be following to see how you make out with the drive test. Cheers

 

[efdog]

Re: 2001 5.7 GI-A overheats

So I just perforemed the clear hose test at the raw water pump. Only air coming to the inlet and only air out...No water at all being sucked up, so obviously there's either an obstruction before the pump, the pump is not pumping, or a major air leak before the pump. If this were an air leak, wouldn't it pump some water up?

The overheat diagnosis manual doesn't go into detail on my next steps. Would it make sense for me to take a hose from the inlet to a bucket of water to see if it sucks it up? Would this confirm my pump / impeller are doing their job?

 

[Don S]

Re: 2001 5.7 GI-A overheats

Would it make sense for me to take a hose from the inlet to a bucket of water to see if it sucks it up?

Sure, give it a try

One question, the boat was in the water when you did the clear hose test wasn't it? It won't tell you much on muffs.

 

[efdog]

Re: 2001 5.7 GI-A overheats

One question, the boat was in the water when you did the clear hose test wasn't it? It won't tell you much on muffs.

Drive inlet holes completely submerged in water using a large 50 gallon rubber tub

Thanks, I'll try the bucket test next

 

[cobalt1999]

Re: 2001 5.7 GI-A overheats

You haven't given a reason for the extensive overhaul, was it for freeze damage? If so, I would look at your power steering cooler which is on the suction side of the raw water pump.

 

[efdog]

Re: 2001 5.7 GI-A overheats

You haven't given a reason for the extensive overhaul, was it for freeze damage? If so, I would look at your power steering cooler which is on the suction side of the raw water pump.

Previous block "torched" as was described by mechanic between cylinder 4 and 6. I'm not 100% sure why blew, but the manifolds / risers, and several other parts were heavily corroded from the previous owner having on a salt water slip for the summer without proper maintenance.

 

[efdog]

Re: 2001 5.7 GI-A overheats

Performed the bucket test, and can now confirm that the pump is not pumping, as it did not suck water from the bucket.

Pump was new with the overhaul...so not sure where to go from here.

 

[jimmbo]

Re: 2001 5.7 GI-A overheats

Is it possible that at some point, perhaps during winterizing the two hoses going to the raw water pump got reversed? That could why it heats on the muffs but not when water is being fed thru the drain line

 

[efdog]

Re: 2001 5.7 GI-A overheats

Thanks Jimmbo...I thought of that as well, and got out the manual to verify just in case. The inlet hose comes in to the top of the pump as pictured.

 

[jimmbo]

Re: 2001 5.7 GI-A overheats

When the impeller was replaced last summer was the old one intact? or did do what mine did and self destruct? the pieces managed to plug up the inlet holes and outlet holes of the pump. It took a bit of work to get them out. Also in the impeller kit i bought there was an o-ring to seal the pump housing. Did that get forgotten? the is also a seal on the shaft the goes into the pump. If it leaks it could suck air

Putting the outdrive in a bucket or tub of water really doesn't do anything with these Volvo I/Os. The raw water pump is not in the outdrive where it can be submerged in water so it can be primed, You pretty much have to put the boat in the water to make sure water gets to the pump. I guess if you were to connect the garden hose to the drain fitting and have the water flowing in to the engine that way when you put the drive in the bucket, that might prime the pump and get the water flowing when you start it. Once engine is running shut off garden hose and see what happens