Will running the shower w/ the engine off cause overheating?

[saswad]

i'm at Lake Havasu on vacation and i seem to be having overheating issues. Today, while just hanging out with the family, one of my kids turned on the shower to participate in a water fight. The engine was off, but the water was extremely hot. After playing with the hot/cold valves a while, I remembered that my mechanic had said something to me once about the shower and I think he was saying not to run it with the engine off. Will that cause overheating issues?

Here's the real problem, it seems like the boat is now running at about 180 degrees. It might drop to 175 or so, but mostly stays at 180. In fact, on one occasion, it probably got to 185+.

My problem is, I don't remember what it ran at before the shower episode today. Maybe it was that hot and I didn't notice, but I seem to think it ran closer to center of the dial which would be 16- or so.

I just had my mechanic change the impeller about 15-20 hours ago. I don't know where the "Streamer" is that some of the posts reference. I was having problems with a leak in my heater, so the guys at the shop told me to by pass the hose with a coupler.

Is it possible that bypassing the heater core could be causing the overheating?

Any suggestions are welcome as my mechanic is closed on monday's.
Am I causeing damage running it at 180?

[Andrew]

RE: Will running the shower w/ the engine off cause overheat

180 is just fine, no where near overheating......

it may depend on how ur heater is plumbed, but i can't think of any reason why using the shower while the engine is off would cause overheating. all i can see that doing is draining all the water from the engine, and after u fire it back up, the engine should start pulling water and be back to normal. are u considering the 180* to be "overheating" or is it getting hotter than that? if u want it to run a little cooler, u can use a lower temp thermostat.

[Laptom]

RE: Will running the shower w/ the engine off cause overheat

180 is running on the high site. But not hot. I think around 165-170 is normal. Let your thermostat check.

The boat needs to be running for hot, but also for cold water!!! The coldwater input is T'ed of after the raw-waterpump. So if the engine isn't running there will be no cold water supply to the shower.

[Andrew]

RE: Will running the shower w/ the engine off cause overheat

these showers don't use an electric pump? how does one use it when the engine is off?

[Laptom]

RE: Will running the shower w/ the engine off cause overheat

Andrew, these showers are using an electric pump. But it's getting it's cold water after the raw water pump. In that way there isn't any delivery of cold water if the engine is off. The raw waterpump acts like a valve when it's off.

[Andrew]

RE: Will running the shower w/ the engine off cause overheat

so, the pump pulls water from between the engine and water pump, correct?

if thats the case, then how does it get water when the thermostat is closed?

sorry for all the questions, i just hate not understanding how sumthin works lol

[Laptom]

RE: Will running the shower w/ the engine off cause overheat

No problem Andrew. I'm a bad explainer (+ European English)...

The shower needs a cold and hot water source.
The hot water source is easy, just tap it of the engine drain plugs at the bottom of the base engine.
The cold water source is a bit more complicated. You cannot tap any cold water before the raw water pump. Then there is no cold water if the engine is running, the raw water pump is so much stronger that it takes al the water from the shower. So you need to tap it after the raw water pump, but before the cold water is reaching the engine. So between the raw water pump and the engine you'll get the source for cold water.
Hot and cold water is then mixed by a mixer and with the help of a small pump to the shower head/sprayer.

The thermostat has nothing to do with the shower.

[DanielC]

like it was said, your shower needs a source of hot and cold water. Hot water comes usually off the engine block, cold water comes from another source, depending on how your boat shower was plumbed. The cold water supply could be on the engine or the lake side of the raw water pump. Usually the cold water supply hose to the shower is blue, and the hot water supply is red. These two hoses go to the mixing valve, and the hoses from there are gray. Using hot water in the shower, will draw hot water from the engine, and may pull lake water into the engine, when the engine is not running. It may also draw air into the cooling system of the engine. Using cold water in the shower with the engine off may also draw hot water off the engine, or cold water from the lake. The shower pump creates a vacuum, and it draws water from whatever source is the easiest to pull from.
When the lake temp. is high, your engine needs more of the warmer water to cool the engine. Your raw water pump impeller is also more flexible, and pumps a little less water. The cooling water also goes through the transmission oil cooler, gets heated a little, and the V-drive, and gets heated a little more, if your boat is V-drive, before it gets to the raw water pump. Take all these factors into account, and that is why your boat runs a little hotter than what is normal, when lake water is warm.
If you can, lift your motor cover when the boat is not running, it will allow the engine to cool a little more on your vacation. Not every time you pause to pick up somebody that has fallen, but when you stop for lunch, or are sitting for a while. When you stop your motor, cooling water stops flowing, and cool air is not drawn into the engine compartment, and the engine soaks in its own heat. 180 is ok, and 185 might be seen, if you run the boat hard, let it sit with the engine cover closed for a short while, and then restart. If it goes above 200, and stays there, be concerned. If you have a newer engine, and it gets too hot, it will go into "limp mode" and not allow you to rev the engine very high, and it will make some cylinders misfire, to protect itself. Under this condition, the engine light on the dash will probably come on.
Running the shower with the engine off may or may not cause a temporary overheat condition. It could actually cool the engine, sometimes, depending on your shower plumbing.

[saswad]

Thanks for the responses. Here's the latest. I posted on sunday. I looked at the strainer and it look ok from the outside. I didn't remove it, as I didn't have a strap wrench. I ran the boat most of the day on monday and it never got upon 180. In fact, most of the day it ran around 170. I noticed my volt meter dropped to 12 most of the time. Based on comments from other posts and comments from a PCM mechanic I called, I was thinking I might be getting false readings from the temp guage. Today, most of the day it ran fine, around 160-170. At the end of the day, I took out the boat for a few hours of flat water. I ran it the boat (2002 SANTE) about 40 mph for 10 minutes to get to the flat water. We ran at 20 mph for about a 15 minute run. At the end of the run, I noticed the temp guage reached probably close to 200 degrees. As I was shutting down the engine, I "think" I noticed the Check Engine light came on. I opened the engine cover and was trying to feel the exhaust elbow and the rubber hose connecting to the muffler. As it was open, I heard this "pooof" (a release of pressure sound). Both of the rubber hoses connecting to the muffler seemed to collapse. I heard some other strange sounds. I thought for sure I had just had a major issue. We sat there for about 5 minutes to see if things cooled off. I started the engine expecting either it to sound like I blew a gasket or bent a rod, or something similar. That or the check engine light would stay on and if I was lucky, limp home.
It turns out the engine sounded fine. The engine light did not stay on and I slowly made my way back home. I got it up to about 20mph and the engine temp seemed to stay around 180. When I got home, the final reading seemed to be around 190. I really don't understand what that "poof" was and why those big hoses seemed to collapse and then seem fine.

I'm very confused. I thought it was a bad guage, but i'm now feeling like there is something else wrong. I've met someone that will help me remove the strainer tomorrow to see if there is anything clogging it.

Anyone have any other thoughts why one day it's fine and then the next it's really hot. I opened the hatch and it really is HOT inside. I'm worried that if I continue to run it over 180, i'm going to do damage that will be very expensive to repair.

[DanielC]

What engine is in your boat, GM, or Ford?

[coloradonautique]

Here is something to keep in mind. I would check to MAKE sure you are getting water to the engine. (Pull the output side of the water pump and ensure it is shooting water, check the thermostat is opening or try running without it installed, check to make sure you are getting water out the exhaust.)

Not sure if this can happen in the these boat engines but I once had an automobile engine overheat because of a leak in the cooling system. The temp gauges never read high because it actually had ZERO water circulating in the system and the temp gauge was reading the "air" in the cooling pipe rather than the temp of the water flowing through the pipe. The engine definitely got very hot before it convected enough heat to the temp gauge through other parts to move the needle. Scary scenario.

Otherwise I have never heard/seen a scenario like that "poof" and collapse of the exhaust pipes. My gut says that's not good. Those are pretty big pipes with not a lot of pressure in them normally (since the exhaust outlet is not sealed, it just has a flimsy flap with free flow to the lake after that.)

Anyone else have any ideas?

[C-Money]

Sounds like a lack of water in the cooling system to me. If there were water in the hoses they would not collapse unless it were being forced out. Only air will do that. If there were mostly air in the system and the boat was sitting still the build up of steam pressure would push the flap open to let the air out of the exhaust. With water on the outside the flap would seal the system creating a vacuum. This could cause the hoses to collapse.

Maybe?

[coloradonautique]

That is what I was thinking, hence the recommendation to ensure water is getting into the cooling system. I have no experience or data to back up the theory... so it remains a tenative "maybe" with me as well.