Winterizing LT1 Questions

[nidus72]

Hi all,

I’ve done a bunch of searches and read most everything I can find on winterizing, fogging etc. But I have a few quick questions to clarify before I do this next weekend. I live in Northern Ontario so it gets real cold all winter and the boat will sit from now (this month) till June before it’s back in the water.

The motor is a 1996 LT1.

1) Fogging with the LT1 engine. Most of the posts seem to talk about shooting some fogging oil into a hole in the throttle plate, behind the flame arrestor? Is this the same with the LT1? Does anyone happen to have a picture of where this is on my LT1? I’m also planning on removing the spark plugs and spraying a little directly into the cylinders.

2) Draining the block. From what I have read it’s not recommend using RV anti-freeze on this motor due to the aluminum heads. If I remove the various hoses mentioned in posts and turn the motor over once or twice it sounds like I should be good. Also need to remove the petcocks on the block. Is there 4 per side?

Thanks in advance for your input
Nidus72

[Patrick Hardy]

nidus72, I have the same engine.
1. I have been told both ways: fog thru throttle / do not fog thru throttle. I have always fogged thru the throttle and have never had any problems doing this.
2. I was also told not to use anti-freeze on this engine because of the heads. I have never used it in the 14 years of ownership. I live in Seattle which is much warmer during the winter than where you are, so I do not get that extreme cold weather.
Yes, there are 4 petcocks, both sides of the block and exhaust manifolds.

[Craig]

1) Don't spray fogging oil into the intake, spray directly into cylinders only. You don't want to foul up your injectors.

2) There are four locations you are looking to remove a plug or other item. On the manifolds, stern side, there are plugs. These can be removed with a 1/2" socket. There are two additional plugs on the sides of the engine block, above the oil pan and below the manifolds. I have a brass plug on the port side and a knock sensor on the starboard side of mine. Remove each of these and make sure you get a good flow of water out of each. If you have a petcock, remove it completely.

Anti-freeze is not recommended.

Take your impeller out of its housing and store somewhere climate controlled, preferably.

Detach the lower end of each of the water hoses on the bow side of the motor and shake out any excess water.

Make sure you also remove your transmission cooler and get any extra water out of it, those are easy to bust.

Throw some Sta-bil in a full tank of fuel, detach the battery, lube up the drive shaft, throttle and transmission cables and you are done.

[nidus72]

Thanks for the quick response!

[skierdan]

sorry to threadjack, but I have a 94 LT1 and I thought i had only 2 petcock valves, the quick disconnect hose and the impellar to drain. Am i missing something? any pictures would be great i am not sure if a 96 LT1 has 4 petcocks instead of 2

thanks

[Jorski]

2 on the passenger side, 1 on the drivers side plus you need to remove the Knock-sensor. I have a '93

[Craig]

Just to clarify, there are 4 holes total that water is drained from regardless of the hardware that is screwed into them.

These are what I call petcock valves:





However, my boat has one of these at the stern side of each manifold (2 total):



I have one of these (brass plug) on the port side of the engine block above the oil pan and below the manifolds:



On the same spot on the starboard side of the engine I have one of these knock sensors:




Bottom line, four holes on the engine, get the water out of there. If you have petcock valves on any of these locations, remove the valve completely.

I think everyone is trying to say the same thing, maybe just different nomenclature.

Hope this helps clarify things.

[Jorski]

One more important tip:

Once you remove the plugs (whtever type that they are) it is critical to poke an awl or something up into the hole and wiggle it around.

Several times I have had rust, scale and muck combine to hold water in the block. That would be a disaster.

[captain planet]

Owner of a LT-1 since 1998 and have put conventional anti-freeze (ethylene glycol) into my block every year and have always fogged through the throttle plate. No problems here.

[east tx skier]

As for fogging, my assumption is that the LT1, being a multiport injected Chevy, is a dry flow manifold and, thus, should not be fogged at the intake. I know that's the case on my dry intake GT-40 MPI engine.

You can fog a wet flow intake though.

[nidus72]

I'm going to fog in the cylinder for sure, but I'm still on the fence on going into the throttle plate since this one seems to less unanimous.

Captain Planet. I’ve seen other threads where you mention that you use antifreeze and you seem to be unique in this manner with the LT1. I know each person has their own unique situation. With me I would feel safer having antifreeze in there since I’ll get days over -40 for sure in the winter where I live. Any little bit of water left in the engine has a potential to cause issues.

If I go the anti freeze route (using some good quality -100 antifreeze) what do you do? Have the boat suck it up through the fresh water intake from a 5 gallon pail until you see it come out the exhaust? I’m assuming you don’t/can’t remove your impeller in this case and just replace it in the spring? In the spring I would need to flush the antifreeze out (collecting it from the exhaust) before putting the boat in the lake so I don’t dump antifreeze into my drinking water.

Also, is the fresh water intake one of the hoses I’ve marked as A or B on the attached picture? I assume that metal budge in the middle is the housing for the impeller.

Thanks
Nidus72 (Dave)

[captain planet]

As for fogging, my assumption is that the LT1, being a multiport injected Chevy, is a dry flow manifold and, thus, should not be fogged at the intake. I know that's the case on my dry intake GT-40 MPI engine.

You can fog a wet flow intake though.

OK, should the MCX not be fogged through the intake as well? My buddy and I typically winterize together, I have the LT-1 and he has the MCX. Both of us fog through the intake and have for years with no problems. Have we just gotten lucky?

[trickskier]

What is this "Winterization" you speak of???

[uncleboo]

I use some marvel mystery oil (per the manual). Also, I fog the cylinders directly. I don't use antifreeze because we live in the South. However, if our winters got to anything negative (let alone -40) then I would 1) move somewhere warmer 2) use some type of antifreeze that was safe for aluminum heads. Change the oil before hibernation, then make sure you use some fuel stabilizer that combats the effects of the ethanol in the gas too.

[east tx skier]

OK, should the MCX not be fogged through the intake as well? My buddy and I typically winterize together, I have the LT-1 and he has the MCX. Both of us fog through the intake and have for years with no problems. Have we just gotten lucky?

I would say lucky. But I'm no mechanic.