Antifreeze Leaking from overflow (454)

[moonlitcoyote]

I have a 454 engine and every time I drive it, the antifreeze leaks out of the overflow tube that hangs behind the front passenger tire. I thought it was due to being overfilled but now I'm not so sure. Has anyone had this problem before or know what I may check to find the problem?

[ClydesdaleKevin]

Could be a couple of possibilities...I'd start with replacing the radiator cap, making sure you get a new one with the same PSI rating.  If its not overfull, then a bad cap can vent too early and leak out the overfill hose.  There are folks here with way more mechanical knowledge than me though, so listen to them when they speak up.  Most of what I know I learned from them, or through empirical knowledge.

Kev

[moonlitcoyote]

I dont know how to explain this so that I may be able to get some help. I assumed the hose hanging down behind the passenger side tire was the overflow, but after checking it out again today, I have NO idea anymore. I cant tell where it originates, but there is a small compartment inside the cab on the passenger side and when I opened it up, it looks like some sort of a cooler or something. It has fins on it like a radiator and that hose is somewhere either behind it or under it. I looked all over the radiator but didnt see a place for overflow to run out. I know on my car the overflow tube is at the top right near the cap, but that is not the case on this one....Any ideas?? I am pretty sure I lost ALL my antifreeze last night while it was sitting in my driveway.

[Froggy1936]

This hose could be the A/C condensate drain hose Wich would also allow a leaking heater core (or hose) to allow coolant to show up there  Easiest diagnosis is to remove both hoses to the heater and jump them together (the two that go to the engine)  then run a garden hose into heater core  and see if water shows up at the drain hose Do not allow a lot of pressure 15 lb max  If its a leaking heater core this is a MAJOR job Frank

[moonlitcoyote]

Well crap, thats not what I wanted to hear. Is there a service manual or something that will tell me how to fix it if I find thats the problem?

[ClydesdaleKevin]

Difficulty of heater core replacement depends on the model of the coach and how and where they squeezed it in under the dash or behind the front cowling.  They can be repaired by radiator shops once you remove it, and new cores can often be had that are exact matches.  Sometimes you can't find a replacement core, but can find one close enough to the original shape like in our 72 Futura, where you can modify the intake and outlet tubes and make it work.

The alternative if you are on a really tight budget would be to bypass the core altogether...pull both hoses off the core, get a piece of tubing the same size as the tubes coming out of the core, and push both hose ends on it with hose clamps.  It will mean your dash heater and defrost won't work, but it will get you going in a pinch. 

That is also another surefire way to test the heater core for leaks.  Do the above, and then see if you are still leaking coolant out that hose...if you aren't, then you've solved the problem and just need to eventually replace or repair the core.

On our 72 Futura, it was easy to get to the core...it was behind the front cowling in a metal box.  The Itasca involved taking half the dashboard apart, and on our 89 HR, it appears that it can be accessed by by simply unscrewing a metal kickplate on the passenger side footwell, from inside the coach.

Kev

[moonlitcoyote]

My main problem with even doing the bypass is the fact that my husband is in Colorado and I am in Maine. I just need to get the Winny up to our place about 177 miles from where it sits right now. Then when my husband gets here at the beginning of June he can take care of it. Do you think if I bring extra water I can make the trip without killing it?

I "can" do the bypass if I knew exactly where the core is and if it was easy to get to, but being just me and the baby makes it difficult to get into anything that takes "time"

[Lefty]

If the leak is severe enough that you lost a lot coolant just sitting in the driveway, then I'd say no.
A leak does two things, both not good.

First, you lose the coolant your engine needs to prevent overheating... and a motorhome is already challenged when it comes to cooling as it is. By the time a temp gauge is in the red zone, your engine can already suffer extreme damage.

Second, a leak prevents the system from operating at it's designed pressure. A cooling system is pressurized to raise the boiling point of the water/antifreeze to prevent the coolant from boiling. If run at atmospheric pressure, and under a load in moderate temps, an engine can easily exceed 215-220 deg. Water boils at 212 deg.... So to prevent boiling, you would have to continually add water AND antifreeze in order to keep the boiling point high enough. A 50/50 mix of antifreeze and water has a boiling point of around 250 deg (varies by brand/type)

I have driven cars that had small leaks in the heater core, but I'm talking about leaks that would take a couple days to leak out maybe a quart. Even then, I wouldn't have put them thru a 170+ mile road trip before fixing them... you never know when that small leak could suddenly rupture into a total failure.

If you can get it to a local garage, they should be able to bypass the heater core for you. It isn't a difficult job, nor does it require more than a coupler and a couple hose clamps. It might require a short length of new hose, if the old hoses cannot be routed to meet up with each other... but most of the time you don't even need hose. Just tell them you want the heater core bypassed.

Shop Charges:
Most repair shops charge a minimum labor time rate, usually either 1/2hr or 1hr. This is at most a 1/2hr job to bypass the heater core and refill it with antifreeze. Shop rates vary, but are usually between $40/hr and $65/hr. here, ask them what their labor rate is, as it varies widely on what part of the country you are in. Supplies needed would consist of 1-2 gal antifreeze, some clamps, the bypass coupling, and possibly some new heater hose (it's sold in bulk by the foot) I would estimate parts cost would be around $15-$30 if you purchased the parts yourself and brought them with you
Antifreeze- $8.00/gal., Clamps $.50 ea,coupler $5.00,Bulk heater hose $1.25/ft (3'-6')
...most shops charge between a 20% and 50% markup on parts that they order, and some shops charge as much as a 100% markup, so it's important to ask what their parts markup is.

It would be worth it for the peace of mind knowing it isn't going to overheat., nor do any additional damage should it suddenly burst completely and leave you sitting on the side of the road.

[ClydesdaleKevin]

And there might be a faster way to bypass the core yourself.  Find the two hoses that go up to your heater core, and trace them back to the engine.  Once you find both outlets at the engine, you can close the loop there...you might even be able to get away without buying any parts if one of the hoses is long enough to close the loop.  You'll have to figure out exactly how you want to do it first, get it all planned out in your head.  Then you'll have to work fast to minimize how much coolant you loose when you are pulling hoses and rerouting them.

Essentially, you'll want to pull both hoses off where they come out of the engine, and then use a piece of hose to go from one fitting to the other, securing them with hose clamps.  The way I would do it would be to find both hoses and fittings, loosed the highest hose's clamp, and then find the hose at the lowest point on the engine, and cut the hose off higher than the engine, making sure its long enough to reach the other fitting.  Hold it up high so you don't loose a lot of coolant...now pull off the other hose from the fitting and quickly push the cut hose onto the fitting, and secure it with a hose clamp.  Tie the other hose and what's left of the cut hose out of the way. 

We got by with a leaky heater core on the Ark for about a month before my friend Tom (slantsixness) helped me replace the core in his driveway.  We did this by simply making sure the little valves that turn the heater on and off were both closed, and securing them in the closed position with zip ties.  This doesn't always turn all the coolant off from going to the core, but it certainly minimizes it.

Kev

[Froggy1936]

The fastest and easiest way would be to (at any auto parts store) purchase 2 hose clamping pliers (they resemble vise grips with no teeth on the jaws) locate the two hoses that go to the firewall and pinch them closed fill cooling syestem and check them at each stop keep an eye on temp gauge Have a safe trip. Frank

[Lefty]

Good tip froggy, I've seen the pliers your referring to but it never even crossed my mind. For her to make the trip, that would probably be the cheapest/simplest solution.

[moonlitcoyote]

Well I bypassed the heater core today, Monday I will buy some antifreeze and start her up to see if there are any leaks. Hopefully I got it done correctly. If not I may have a mess on my hands

[ClydesdaleKevin]

You are like Wonder Woman girl!  Doing all this stuff with a baby in tow is not easy!  Hopefully that will solve the coolant leak, and you'll be able to take your time and replace the core when you can.

Kev

[moonlitcoyote]

Thats what I am hoping Kev, I almost pulled the core yesterday but couldnt quite figure out how to get it out. Had most of the dash pulled apart but still couldnt quite get to it enough. Oh well, I'll get it out before winter gets here.

[moonlitcoyote]

So I got her filled back up with antifreeze and let her warm up for about 20 minutes. NO leaks anywhere and she stayed on the cool side, so I should be good to go. Or do you think I need to let her run longer?

[ClydesdaleKevin]

Depends on the ambient temperature outside, but I'd say she should be more than fully warmed up in 20 minutes.  Glad there aren't any leaks! 

So now you can drive it, and that will give you until winter to replace the heater core.  Your defroster won't work nearly as well without heat, so use some Rain-X on the outside of the windshield, and that Fog-X stuff, I think its made by the same company, on the inside of the windshield, in case you get stuck in the rain.  It makes is a LOT easier to see!

  Awesome job!

Kev

[Froggy1936]

In case of emergency (inside of windshield fogging up in the rain)  The air conditioner will clear the glass thru the defroster ducts (if they are still intact)  Frank

[moonlitcoyote]

Thanks for that info, I am taking her up north Saturday and then she wont be moving until after hubby gets here, so I should be good. It's supposed to be 62 and sunny on Saturday

[moonlitcoyote]

Problem... I dont remember where I took the hoses from in order to put them back

[Stripe]

The small or large ones?

[moonlitcoyote]

small hoses coming from heater core

[DaveVA78Chieftain]

I take it you placed a loop on the in out engine ports (water pump nipple and thermostat nipple?). 
Thermostat nipple (hot water source) would go to control valve (prevents residual heat from getting to heater core).   
Control valve to either heater core nipple. 
Other heater core nipple to water pump nipple (acts as a suction port).

Dave

[moonlitcoyote]

would you happen to have a diagram of where the hoses from the heater core go? We have searched the engine but cannot figure out what I did, lol. It was too long ago I guess.

[DaveVA78Chieftain]

Because Winnebago installed the dash heaters, GM did not put a P30 heater hose diagram in their manual. 
My guess though is the hot side supply nipple is on the intake manifold next to the thermostat housing and the return line is connected to a nipple on the top of the water pump.  A couple of GM pickup setups had the return line connected to the top of the radiator.

The supply line from the intake manifold would be routed to the temperature control valve which is most likely cable controlled.

If there is truck junkyard in the area, you might be able to locate a used heater core from a school bus, bread truck, or something like that.

Dave

[M & J]

Why couldnt the radiator shop fix the core MJ?