Overheating?

[nate44]

This in reference to my exhaust manifold on my straight six cylinder chevy.
I put a new water pump on it. I am getting water into my manifold and it is flowing out of the manifold.
What should the temperature be for the exhaust ports going into my block?
My friend is getting a gun or whatever to check the temperature throughout my system.
I am also getting water throughout my block.
My only concern is that is seems the exhaust ports going into my block are really hot.

thanks again for all your help

oh yes,
can the inside of a manifold get so rusty corroded that it can't absorb the cool water ? and lower the temp down?

naten

 

[HT32BSX115]

Re: Overheating?

The actual exhaust flanges/ports don't have coolant (or water) flowing in them. so they usually look like they get hot (and they do) but those are probably only a couple of inches long at most.

It's very possible that your manifold plugged in several areas in such a way as to restrict/block water flow in that area. This will cause localized hot-spots in the manifold or cause a hot spot at the point where water exits since there's not enough flow to keep things cool.

This usually signals the time to buy a new one.

Exhaust manifolds and riser/elbows have a definite life. They either clog up and start getting hot or they rust thru and ruin your engine.

They're not that expensive to replace. (by comparison to the whole engine)

Also, if you boat in salt water the manifolds rust a "bit" faster. Well, maybe a lot faster.

Remember that the manifolds and risers are usually cast iron....like the block. So the block will rust too, along with the head. The block and head can get clogged with rust just like the manifold. Depending on how diligent one is with flushing out a salt water cooled engine after use will also determine how the whole mess lasts.



Regards,


Rick

 

[nate44]

Re: Overheating?

do you have any idea what the temp should be around on the exhaust ports going into the block?

 

[HT32BSX115]

Re: Overheating?

I can't tell you that. I have never measured it. I can tell you that it's normally hot enough to burn the paint off. You can usually tell where the "water-jacket" area starts because the paint doesn't ever burn off there. it'll usually be an area between the manifold and head from the (exhaust) flange where it bolts to the head to the main body of the manifold.

Those "runners" are usually only an inch or two long but they are usually never "jacketed" so they get pretty hot.

The main "body" of the manifold should not get hot enough to burn you. I.E you should be able to put your hand on most water jacketed manifolds briefly and not get burned. If it's REALLY hot, you're probably not getting enough water flow thru it either due to a bad raw water pump or blockage or both.

 

[nate44]

Re: Overheating?

ok
my main portion of the manifold is not to the touch, just those short "runners" an inch or 2 long that bold to the engine. So maybe i'm just over re-acting. I haven't had an i/o for a while and just thought that they shouldn't get that hot.


thanks again

nate

 

[HT32BSX115]

Re: Overheating?

I don't know about the 165 manifold (it's an intake/exhaust combined right?)

You can usually sort of see down into them with the elbow removed. You should probably remove the elbow just so you can check the gasket to ensure that it's not leaking (of course if you remove it you absolutely should replace the gasket.

With the elbow off you can look in and see if there's a lot of rust growing in there and clogging it up. If there's a LOT in visible areas then there's probably a lot in the invisible areas......time to replace it and probably the elbow.

Flow restriction, if severe enough in the manifold and elbow, almost always results in overheats.....(check the raw water pump first though)

Sometimes the over heat might be caused by raw water pump fragments that came from a previous failure.

 

[arks]

Re: Overheating?

Measure the temperature of the exhaust manifold in a few places. If you see any reading over 180 then you've got a problem. Could be any number of things.
Get yourself an infrared thermometer like this one; they can be had for under 50 bucks:

 

[ziggy]

Re: Overheating?

This in reference to my exhaust manifold on my straight six cylinder chevy.
I put a new water pump on it. I am getting water into my manifold and it is flowing out of the manifold.

that sounds good.....

What should the temperature be for the exhaust ports going into my block?

So maybe i'm just over re-acting.

perhaps, don't ya have a temp gage onboard? what does it say? my L6 just has red and green for temp. normal is on the low side of green with a known good tstat and a fresh impeller........ i don't feel the need to test any further.... i do have a year old manifold and riser though. if yers is old or of unknown age. it may be worth gunning it or physical inspection.. may lead to early detection of failer. as my impellers wear. i find my temp gage goes up too. more and more the older it gets... that's my sign that it's time to check it out.... i live by my temp gage. that and oil pressure....