5.7 overheating at idle

[69GTOby]

Re: 5.7 overheating at idle

For what it's worth, my '88 Baja 350/260hp Alpha1 had the same prob. Would not cool at idle, but would cool just fine when moving along, or just floating and reving the engine. It ended up that the hose in the bellows area that brings water from the impeller in the drive up to the engine somehow popped off the nipple on the outdrive. So, it was relying on the pressure pump on the side of the engine and the circulator pump on the engine to suck up water.

 

[joewithaboat]

Re: 5.7 overheating at idle

I would oblige Bond-o with the picture he requested, he will be able to look at it and see if anything is plumed wrong, very quickly.

 

[JOEP2]

Re: 5.7 overheating at idle

''pressure pump on the side of the engine ''

This is the pump I was wondering if I need, mine doesnt have this, it does show this pump on a alpha 1 with a 350/260 with out a fresh water system.
Im going to pick up a neused (known good) alpha 1 lower this evening and install it tomorow morning along with the balls being installed in the thermostat housing.
If this doesnt fix it Im having a bbq in my back yard, whos bringing the marshmellows?

 

[69GTOby]

Re: 5.7 overheating at idle

Make sure the new/used lower unit is the correct gear ratio. Good luck.

You can have the BBQ anyway LOL I'll bring the marshmellows, and some beer.

 

[Bondo]

Re: 5.7 overheating at idle

Make sure the new/used lower unit is the correct gear ratio. Good luck.

You can have the BBQ anyway LOL I'll bring the marshmellows, and some beer.

Ayuh,... In the Alpha 1, 'n those before it, the Ratio is in the Upper,...
The lower units are the same...

''pressure pump on the side of the engine ''

I'm curious as to what the 'ell you guys are talkin' about,..??..??
Picture,..??
Diagram,..??
Link,..??

 

[JOEP2]

Re: 5.7 overheating at idle

On one of the coolant flow diagrams, it shows the water coming up from the lower unit, to the aux pump mounted on the side of the engine (which is driven by the belt system), then goes thru the power steering cooler, then to the thermostat housing.
I also thought the ratio of the gears was in the upper, was just about to sak what the h*** myself.

 

[Don S]

Re: 5.7 overheating at idle

It ended up that the hose in the bellows area that brings water from the impeller in the drive up to the engine somehow popped off the nipple on the outdrive. So, it was relying on the pressure pump on the side of the engine and the circulator pump on the engine to suck up water.

Assuming you are referring to an engine mounted raw water pump when you say pressure pump, you should start a thread of your own on how to properly fix your system, because that is NOT how your system should be hooked up.

Oh, an engine circulation pump can not suck up water, it can not create a vacuum.

 

[Don S]

Re: 5.7 overheating at idle

On one of the coolant flow diagrams, it shows the water coming up from the lower unit, to the aux pump mounted on the side of the engine (which is driven by the belt system), then goes thru the power steering cooler, then to the thermostat housing.

You either use the engine mounted raw water pump, or the one in the outdrive, but NOT both.
The drawing may show both options in the same drawing, but not being used at the same time.
BTW, what manual are you looking at? OEM? I would like to look at that picture.

 

[Bondo]

Re: 5.7 overheating at idle

On one of the coolant flow diagrams, it shows the water coming up from the lower unit, to the aux pump mounted on the side of the engine (which is driven by the belt system), then goes thru the power steering cooler, then to the thermostat housing.
I also thought the ratio of the gears was in the upper, was just about to sak what the h*** myself.

Ayuh,... It's Not an Auxiliary pump,...

You have 1, or the Other,... Never both...
Either a raw water pump in the outdrive,...
Or,...
A raw water pump belt driven on the motor....

The motor's circulating water pump does just that,...
It circulates the water given it by the Raw water pump, til it's explelled at the T-stat housing...

 

[JOEP2]

Re: 5.7 overheating at idle


Here is the pics of my water hose routing, see anything wrong with how there ran? Im going to install the balls today and recheck all the hoses for any blockages, but the blue hose where it goes into the power steering cooler is where I have been pullng it off an found the water pulses when running.

 

[JOEP2]

Re: 5.7 overheating at idle

also the blue hose is 3/4" which is what the brab plastic fitting is off the out drive, then from the power steering cooler on it goes to 1'' thru the rest of the system. the blue hose is silicone hose we use on big industrial generators at work, there are no kinks or extreme bends in it to reduce flow.

 

[JOEP2]

Re: 5.7 overheating at idle

Well I feel like a complete idiot. I reinstalled the balls in the thermostat housing and before I did I stretched out the springs some since they felt soft to me(plus all the post on here about them). Reinstalled the hoses, hooked up the garden hose, started it up, ran for about 25min at idle. Motor got to 150 and stayed there ( I have a 140 thermostat ). Reved it up a few times to about 2000-3000rpms for a min or so, got to 160 and stayed there. I guess the first time I had the balls in there there just wasent enough spring pressure on the balls to make them do there job. As it was running i had my hands on the hoses coming from the thermostat housing to the exh manifolds and it was warm the whole time, the hoses attached to the tee fitting where the balls go stayed semi cold the whole time.
I feel like a freaking dumb a** for not catching this the first go round when I started messing with the balls to begin with. Im going to try to water test it tomorrow if the wife and kid are up to it. I'll let you all know how it goes.

 

[Bondo]

Re: 5.7 overheating at idle

also the blue hose is 3/4" which is what the brab plastic fitting is off the out drive, then from the power steering cooler on it goes to 1'' thru the rest of the system. the blue hose is silicone hose we use on big industrial generators at work, there are no kinks or extreme bends in it to reduce flow.

Ayuh,... That's Supposed to be a 1" hose...

There's Supposed to be a rubber collar that goes on that barb, that spaces it out to 1"...
Like a 1" piece of 3/4" hose on the barb, 'n the 1" hose Over the whole thing, 'n clamped on top of 'em...
The P/S cooler is usually Under the motor mount, instead of on top of the motor too...

Glad ya found yer Issue...