Water circulator pump question...

[reimelss]

On a 1997 Merc 350...
Should the water in the hose from water circ pump to the thermostat be hot?
And should it be hotter on the starboard side than on the port side?
just seems like everything on the starboard side is running hotter than the port including manifolds/risers.

 

[HT32BSX115]

Re: Water circulator pump question...

Howdy,

It should warm/hot when the t-stat is open.

Hot coolant flow is INTO the intake manifold from the front of the heads and out of the intake manifold through the T-stat.


There's also usually some bypass through t-stats so if the stat is closed there'll be a little hot water flow anyway.


Most of the raw water from the drive goes right on past the engine right to the manifolds/risers.


Did you "shoot" your manifolds & risers with a heat gun?

Or are you doing it by feel?

 

[reimelss]

Re: Water circulator pump question...

I felt it.
I could hold my hand on the strbrd side riser for like 2 seconds compared to the port side at 10-15 seconds.

But should the water already be hot in the hose on its way from the circ Pump to the therm...before it even gets to the exhaust?

the same hose on the opposite side is not even warm.

 

[HT32BSX115]

Re: Water circulator pump question...

The water from the t-stat housing may be warm/hot depending on how "open" the t-stat is (and how hot the engine is)

Even if it's completely OPEN, it shouldn't be much hotter than about 150F or so....


If one riser is REALLY hot and the other one is completely cold, you may have more blockage (due to rust/debris) in one over the other.

Or the the little "check balls" (if installed) may be blocked by impeller fragments/debris etc on one side.......causing a flow difference on one side over the other.....

 

[reimelss]

Re: Water circulator pump question...

The water from the t-stat housing may be warm/hot depending on how "open" the t-stat is (and how hot the engine is)

Even if it's completely OPEN, it shouldn't be much hotter than about 150F or so....


If one riser is REALLY hot and the other one is completely cold, you may have more blockage (due to rust/debris) in one over the other.

Or the the little "check balls" (if installed) may be blocked by impeller fragments/debris etc on one side.......causing a flow difference on one side over the other.....

The port is still hot but not as hot...
I cleaned out the manifolds/risers..

Ill have to look at the check balls...im not sure they are installed though.
could my water circ pump be broken?

 

[HT32BSX115]

Re: Water circulator pump question...

The circulating pump does not affect how much flow you have thru the risers.....it only affects flow through the engine.

The raw water pump, hoses and associated oil/power steering coolers (if installed) can affect total flow.

 

[reimelss]

Re: Water circulator pump question...

The circulating pump does not affect how much flow you have thru the risers.....it only affects flow through the engine.

The raw water pump, hoses and associated oil/power steering coolers (if installed) can affect total flow.

no oil or power steering cooler installed

 

[HT32BSX115]

Re: Water circulator pump question...

If either of your risers were blocked enough where you could see and "clean" them.

They're usually also blocked where you cannot see or clean them.