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prostar205
01-03-2005, 01:31 AM
My new heater is blowing nothing but cold air. The fan runs fine, I just get cold air. I checked the water connections on the block (next to the knock sensor) and the water is flowing. I also disconnected both the output and return hoses that feed the heater and blew air thru one side and it came out the other end indicating that I do not have a blocked water hose. What could it be?

The boat is a 2002 X30 with the 8.1L engine (what a monster)

Thanks for the help.

jimmer2880
01-03-2005, 07:56 AM
Mine won't blow hot air until the engine is turning more than 1500 RPM's. HeaterCraft has a low-speed kit for the heaters, but I understand that although it makes it a lot better, there's still no heat at idle. Also - It won't make any hot air until your engine temp starts to register on your guage.

Have you tried it out running around the lake?

prostar205
01-03-2005, 01:08 PM
We had the boat out for 2 hours on the lake on Sunday. I checked the heater vents both at idle and under power. Unfortunately, there was no heat either time.

Any other suggestions?

AirJunky
01-03-2005, 03:03 PM
So cold water is coming from the engine? Is it hooked up backwards? Is the thermostat blocked?
I have the Y in my 205 bringing water from the raw water pump & the heater does pretty good at 600 rpm. It does have to warm up but works great after the engine has been running for 5 or 10 minutes.

lakes Rick
01-03-2005, 03:10 PM
Sounds like your connections are either both pressure or suction... Pull each one seperate while the engine is running and see what happens.....

prostar205
01-03-2005, 03:11 PM
I think my problem is that the supply origin is not capable of suppling the necessary volume of water. The supply is on the block next to the knock sensor. I will have it re-plumbed.

AirJunky
01-03-2005, 03:16 PM
As I recall the supply line is usually on the water pump on front of the engine. So you'll need either the hose fitting on the engine water pump or call Heatercraft & tell them you would like the Y adapter to put the supply line down by the raw water pump (more volume).

prostar205
01-03-2005, 03:30 PM
AIrJunky -

I just got off the phone with Heater Craft and you are correct. The way it is hooked up now is more like a shower. They said the typically the supply side is plumbed from the large hose off coming off the water pump. Also, there are usually 2 plugs in the water pump that are suction that are used for the return. Looks like I will have to have it re-plumbed.

André
01-03-2005, 05:39 PM
Not sure if it's a good thing to move the knock sensor from it's factory location on the block...Anybody? JimN?

prostar205
01-03-2005, 06:10 PM
I actually did not move the knock sensors from their original locations on the block. Notice I have used the phrase "knock sensors". To my amasement, there are 2 knock sensors on the 8.1L engine - one on each side of the engine. There are two additional threaded holes on each side of the engine, just above the knock sensor locations. The shower is plumbed into one of the additional holes and the supply for the heater is plumbed into the other. Regardless, the supply line for the heater needs to be moved - as I understand it.

André
01-03-2005, 06:38 PM
My mistake,sorry!
We don't see a lot of peoples on the board with 8.1 ...That thing must sip if your hard on it!

prostar205
01-06-2005, 02:18 AM
Does someone have any pictures of where the supply and return hoses should be plumbed in on an 8.1L engine for the shower. As I mentioned, mine are plumbed to the block drains and it just does not provide a large enough pressure head to "push" the water thru the hose and hence thru the heat exchanger.

Any help would be much appreaciated.

lakes Rick
01-06-2005, 11:31 AM
Prostar, I do not have an 8.1, but my intake, for the heater, comes off of my intake manifold, as in most cars do.. The hottest water will be at the top of the engine, as most flow from the bottom up.. That is why the Lt1 ( or its variants) had a reverse flow cooling system, to cool with the water coming out of the radiator to the Heads first and flowing down into the block..

Anyway, I have a valve I can shut off any water getting to the heater at the intake manifold...

NSXBill
01-06-2005, 12:17 PM
See this thread for a few pics of install on TBI...

http://www.tmcowners.com/teamtalk/showthread.php?t=1102

prostar205
04-25-2005, 02:46 AM
OK - more on the heater (really, its an air conditioner). I took the boat out this weekend for 4 hours. I still have no heat. I have confirmed a few things.

1) my supply side comes directly off the thermostat housing. This is the factory location for the supply side. I took it apart, thinking there was some sort of blockage, but it is clean.

2) the return side is plumbed into the lower portion of the block, next to the knock sensor and the port side of the boat.

3) While out on the boat this weekend, it disconnected the return hose from the block and turn the engine over. There was a steady stream of very hot water coming from this return side. However, there was no water coming out of the block which leads me to believe the return water from the heater hose should be able to go back into this block location.

So, what am I missing. I still have no heat. All of my testing was done at idle. Could it be possible that once the engine RPM is raised, the block drain has positive pressure and does not allow the heater water to flow back into the block, thus leaving no circulation water in the heater hose?

This is getting frustrating - I need heat.

erkoehler
04-25-2005, 06:54 AM
Why? It can't be that cold! :D

jimmer2880
04-25-2005, 07:21 AM
OK - more on the heater (really, its an air conditioner). I took the boat out this weekend for 4 hours. I still have no heat. I have confirmed a few things.

1) my supply side comes directly off the thermostat housing. This is the factory location for the supply side. I took it apart, thinking there was some sort of blockage, but it is clean.

2) the return side is plumbed into the lower portion of the block, next to the knock sensor and the port side of the boat.

3) While out on the boat this weekend, it disconnected the return hose from the block and turn the engine over. There was a steady stream of very hot water coming from this return side. However, there was no water coming out of the block which leads me to believe the return water from the heater hose should be able to go back into this block location.

So, what am I missing. I still have no heat. All of my testing was done at idle. Could it be possible that once the engine RPM is raised, the block drain has positive pressure and does not allow the heater water to flow back into the block, thus leaving no circulation water in the heater hose?

This is getting frustrating - I need heat.

My heater pulls off of the water pump (not the raw-water - the regular automotive style), then back into a port in the intake. It sounds to me like you have a supply, but not a place for it to go.

prostar205
05-09-2005, 12:16 PM
I HAVE HEAT!!!!! :) :) :)

I installed the HeaterCraft "Y" pipe on Saturday and that fixed everything. I ran the boat on the trailer for 10 minutes and at idle, the heater pumped out nice warm air. Running the boat on the trailer probably burned around 5 gallons of gas (I have the 8.1L in her) but its fixed. I can't wait to take it out in the AM and feel the heat at my feet.

Thanks AirJunky for the info on the "Y" pipe.

NSXBill
05-09-2005, 12:26 PM
Anyone have pictures of this "Y" fitting installed?

Engine Nut
05-09-2005, 12:42 PM
I actually did not move the knock sensors from their original locations on the block. Notice I have used the phrase "knock sensors". To my amasement, there are 2 knock sensors on the 8.1L engine - one on each side of the engine. There are two additional threaded holes on each side of the engine, just above the knock sensor locations. The shower is plumbed into one of the additional holes and the supply for the heater is plumbed into the other. Regardless, the supply line for the heater needs to be moved - as I understand it.

Here is the heater plumbing for an 8.1L.

Engine Nut

cdewet
05-09-2005, 01:43 PM
Prostar 205, since you've found your heat, I guess this won't be of much use to you, but it might be for someone else out there with similar issues.
The engine cooling system works as follows:
The water pump sucks (read low pressure) cold water out of the lake/ocean/pond/bathtub and then pumps (read high pressure) it into the engine block and around the cylinders. It then returns through the cylinder head of the engine to the thermostat. The thermostat, when cold, directs the water flow back through engine with only a little bit by-passing the thermostat and out the exhaust. As the engine heats up, the thermostat opens the flow to the exhaust and closes the recirculation loop so more cold water gets pumped through the system and out the exhaust. The thermostat will move between fully opened and fully closed, thus regulating the engine temparature.
The heater circuit takes off just before the thermostat, in other words the high pressure water returning from the heads. The circuit would be the first to warm up and will always be the hottest. The circuit returns to before the water pump (low pressure).
So, in your case, your take-off should be at or close to where your water temp sensor it which is usually close to the thermostat and the return somewhere before the water pump.

prostar205
05-09-2005, 01:52 PM
cdewet -

Yes, my hot water supply come directly off the t-stat housing, as shown in Engine Nuts pics (thanks for the pics). However, for the return side, I spliced the "Y" pipe between the raw water pickup screen and the strainer/trans heat exchanger. It feeds the heater water back into the cycle before the strainer.

It appears to work great - especially at idle. My 8.1L engine runs at 160 degree all the time.

jimmer2880
05-10-2005, 05:40 AM
I have had a heater for about 4 years now and absolutely love it. Although, until last weekend, I didn't have the Y adapter for low-speed heat. That thing works wonders! Not only do I now have heat at idle speeds, I also have hotter heat when on plane. That $30.00 for the "Y" fitting was worth every penny.