Engine temp climbing at WOT

[Lift12]

Hello all,

My 1989 boat has twin 5.7s with Alpha One gen 1 drives. The port engine (0C523213) is getting hot only when running at or near WOT. It runs normally at 3500 rpm but above 4000 it climbs. I've never seen how high it goes as I back off when it gets up to the 200 range. Stbd engine does not have this problem. I replaced the entire water pump assemblies in both drives over the winter.
Port drive also received a new upper half (SEI).

Thoughts on what might be causing this?

 

[GA_Boater]

Was the port motor temp climbing last year before the water pump replacement?

 

[Lift12]

I don't know GA. Boat is new to me and I only went out once for a quick trial last fall on the starboard engine. Port drive/engine was inoperable on that test due to stripped upper drive gears, hence the new upper.

 

[achris]

2 ways to approach this problem.
First is to guess at what it might be, then throw money (in the form of parts) at it.
Second is to perform a few simple tests and troubleshoot it properly.
Your choice.

Me, I'm a troubleshoot sort of guy.

Put a clear hose in the water line coming from the transom to the engine. Watch for bubbles. If you have bubbles we look at the drive (water pump, water pocket cover). If there's no bubbles, we'll move on to an output test....

Chris...

 

[Kola16]

Is it saying 200 on the gauge? My 5.7 says it is 200 on the gauge, but it actually only gets to 165. I bought a $25 infrared light to confirm the running temperature. Is the motor running any differently?

 

[Lift12]

Me, I'm a troubleshoot sort of guy.

Chris...

Me too Chris. I'll try the clear hose and report back.

Lola, if the Starboard climbed in the same way as the Port probably wouldn't be as concerned. I have no reason to suspect the gauge as it seems to read an expected temperature at lower speeds.

 

[Scott Danforth]

step 1 - test and diagnosis

clear hose test
validate temp with IR thermometer
measure Raw water flow rate

step 2 - check normal suspects
impeller
back-flush system (especially the PS cooler)
check for cooling system blockages
check timing

step 3 - fix what needs to be fixed.

your still in step 1

 

[Benny67]

Uhh... just a thought, but did you check out the thermostat? It might be not completely opening and restricting a full on coolant flow at higher rpms

A $6 part and a 1/2 hr labor....might be the issue.

At least a good simple start

 

[Benny67]

Put a clear hose in the water line coming from the transom to the engine. Watch for bubbles. If you have bubbles we look at the drive (water pump, water pocket cover). If there's no bubbles, we'll move on to an output test....

Chris...

He claims the port side upper drive was replaced.

Was it new or a rebuild? If it was a rebuild, the clear hose test OR thermostat would be the first order of business...either one would be an equally rational start to finding the issue

 

[achris]

Uhh... just a thought, but did you check out the thermostat? It might be not completely opening and restricting a full on coolant flow at higher rpms

A $6 part and a 1/2 hr labor....might be the issue.

At least a good simple start

This is what we call the 'shotgun' approach. And it's exactly this method that I find abhorrent! It's great for making the parts supplier very rich, and you much poorer.

'Only' $6 of parts. But $6 here, $6 there, another $10 here... It adds up, and it may or may not fix the problem. Your time is free (unless you are doing this instead of doing something that actually makes you money). Use it wisely and you can save a heap of money on parts. Just replace what needs to be replaced.

Chris.........

 

[Benny67]

This is what we call the 'shotgun' approach. And it's exactly this method that I find abhorrent!

Chris.........

LOL...sorry my approach isn't to your liking..i'm just offering advice. no need to be arrogant about it. Aren't you a moderator? I'd expect a kinder approach from a moderator instead of a snippy,rhetorical remark attempting to discredit my contribution and make yours more intelligent.

also,

IF...he really wanted to save $6 he could just take the thermostat out and dunk it in hot water to see if it functions properly.

Also,

seeing he has no prior knowledge of the boat AND he's having issues overheating, changing the thermostat is an investment in the future of less worrying.

A part under $10 in a troubleshooting approach isn't frivolous.

 

[Benny67]

Uhh... just a thought, but did you check out the thermostat? It might be not completely opening and restricting a full on coolant flow at higher rpms

A $6 part and a 1/2 hr labor....might be the issue.

At least a good simple start

Actually, if you read what I said, I SUGGESTED CHECKING the thermostat...then wrote, "A $6 part and 1/2 hr labor..might be the issue"

i didn't write "change the thermostat"

 

[havoc_squad]

This is what we call the 'shotgun' approach. And it's exactly this method that I find abhorrent! It's great for making the parts supplier very rich, and you much poorer.

'Only' $6 of parts. But $6 here, $6 there, another $10 here... It adds up, and it may or may not fix the problem. Your time is free (unless you are doing this instead of doing something that actually makes you money). Use it wisely and you can save a heap of money on parts. Just replace what needs to be replaced.

Chris.........

Just to reinforce AChris's point..

Throwing parts at problems by guessing instead of diagnosing promotes bad habits that makes those learning engine repair worse off, not better.

In some fields of expertise depending on the subject, it even can kill the operator and passengers.

Do you want an airline parts changer as the mechanic working on the next passenger plane you fly on?

I didn't think so.


For most non-life threatening issues not health related being diagnosed, parts changers end up just wasting lots of money on parts that don't need replacement.

Yes, we've all assumed to some extent a few rare times on guessing for a solution.

The key is the wise ones don't allow that to be a habit.

Why do you think certain auto service shops who are incompetent and possibly crooked are hated so much, they throw parts at problems and try to get the customer to pay for guesswork instead of directing the customer to the services of a qualified expert if they cannot diagnose it.

 

[Benny67]

Just to reinforce AChris's point..

Throwing parts at problems by guessing instead of diagnosing promotes bad habits that makes those learning engine repair worse off

Did you read my last post?

I wrote, "check the thermostat"

Where is this "guessing" this is part of the coolant system and he's overheating.

It's step 1 in troubleshooting a cooling system...

A few of you guy's here create drama in everyday issues to make yourselves seem like you're some sort of genius at solving complex problems.

If i was a parts "chucker" I would have said, change it...I never wrote that.

 

[Benny67]

In some fields of expertise depending on the subject, it even can kill the operator and passengers.

Case in point...

Now THATS a bit dramatic

 

[Lift12]

Both thermostat housings removed, cleaned, painted, new gaskets, spacers and 140 degree thermostats. I will try swapping them between engines to see if it changes anything. One could easily be defective. Thanks for the thought.

BTW that thermostat is a $25 part here in Canada. Maybe more at my snooty marina nearby.

 

[Benny67]

Are these motors FWC or raw water?

 

[wellcraft-classic210]

Hold your ground Benny !!!!!!!!!

 

[scoflaw]

Go Benny go....

 

[Benny67]

Hold your ground Benny !!!!!!!!!

I gotta tell ya...it's a tough crowd here.

i come here to keep my skills sharp and stay informed...but I stay for the fights.