Heater Core hose hook-up

[Graham]

Thanks to both Kwilford and Webster I was able to figure out the coolant hose connections, however the previous owner had an in-line water heater that was hooked up some how over the passenger wheel. I say this because the car was in pieces when I got it. The problem is that there is an extra coolant line coming from the bottom passenger side of the engine just behind the oil pressure guage (presumably the line went to the long gone in-line heater) . Is this line connected to the rear drain plug? What should I do, just plug the hose or take it back to the block and shut it off there. Any suggestions. If I plug it at the block, where do I get the plug? and how do I get at it?


Another question: There is a black wire with an "O" ring connector on the top side of the heater blower, where or what does it connect to?


Thanks.

[opelmark]

Graham, that black wire with the o-ring is the ground wire for your fan motor--you can ground it to the body just about anywhere, and have a working fan, but it's usually grounded next the the hot (red) wire, on the underside of the heater assembly. As for the first question . . . they say a little knowledge is a dangerous thing--remember, the Previous Owner of almost ANY Opel was a wrongheaded dullard, the Guy Who Knew Better, and the root of most Opel evil. Undo what the P.O. did. Quickly.

[opelmark]

I think if it were my engine, and the P.O. did actually remove the drain plug in the block (like that was necessary--he could have "tee'd" off a heater hose, like you would to supply a water choke), I'd find another drain plug, and stop that nonsense at the source. With most GT parts I could help you out, but to be honest, I'm very reluctant to even try removing a plug from one of the spare blocks in the garage--for one thing, after 30 years of rust and scale building up behind the plug, they might be REALLY difficult to remove without destroying them, and for another, you would probably be better off finding a new, unrusted plug of the right size. I don't know what size the block drain plug is, offhand, but someone here might, or you could talk to Gil. A new plug seems like the safer way to go--that engine coolant's fairly IMPORTANT, isn't it? Nothing kills Opel motors--especially heads--faster than heat.

[RallyBob]

Originally posted by opelmark I don't know what size the block drain plug is, offhand, but someone here might, or you could talk to Gil.

The coolant drain plug for all 1.9's (except 1975) is 14 mm x 1.5 PIPE thread. 1/4" pipe thread is almost exactly identical, and will interference-fit well.

Bob

[Graham]

Thanks to Webster I have progressed, however I am stuck on what the correct configuration of the hose hook-up is. Attached is a segment of Webster's photo. Can anyone point out the hose hook-up from the heater firewall.

1) Does the hose on the bottom of the page (Photo) represent the lower hose coming from the firewall, which goes into the water pump?

2) Does the hose coming from the firewall going into the heater valve represent the upper hose?

Or do I have this backwards?

Help

[opelgal33]

I cant get this picture you are talking about to come up. But I have a great copy of the Water hose connections, if you are going by websters picture in the photo gallery.

The Bottom hose on the picture goes from water pump to a "T" and connects to tubes at firewall

The next hose up goes from Heater Valve to firewall.

I can fax you this copy if you have access to a fax. I got mine from OGTS and it was a life saver. Has vaccum hose hook ups too.

Jennifer

[Graham]

Jennifer, (OpelGal33)

Thanks for the info. If you can, please fax me a copy of your photo at my office Fax which is: (819) 994-5836.

Thanks a lot, with your help I might be able to get the car started this weekend.

Regards Graham

[opelgal33]

Graham,

I didn't realize webster had a picture of the hook-ups in his album. It is the same thing I have. It is a great picture, you should be able to read where everything goes.

Jen

[Graham]

Jen, here is my problem.

The two heater hoses on the bottom left of the page (Websters photo) do not indicate from which heater hose (coming from the firewall) that they are attached to. Is the one with the heater valve attached, connected at the firewall to the upper or lower heater core tube?

[opelgal33]

Just went to look in my car.

The upper hose from firewall goes to heater valve

The one under that goes to the water pump connected on the radiator.

Does that help?

Jennifer

[kwilford]

I don't think it matters much from the heater core's perspective, and I can't help much since my hoses are both currently disconnected. Along with the motor. And front and rear suspension clips.

But if the control cable comes out between the heater core tubes as mine does, it looks like it is a better fit to put the valve on the lower hose. Just try it both ways and see which fitment works better with the valve cable.

[webster]

First, it does matter which way u hook them up because of the direction of flow, hot water comes from therm. housing to choke to heater valve to heater box to return line where "T" joins returning water from choke and heater box to pump . second, the lower hose comming from fire wall (as in pic) goes to the heater valve connector. The upper hose goes to the pump. Hope this helps.
Where's the Beer?? LOL
Good luck.
Webster

[opelgal33]

webster that is not how the picture looks either. The very bottom hose looks to be going to the water pump and the one up from that to the heater valve.

I can't say mine is right, since I know the PO did some goofy things to this car. But that is one problem that I haven't had to deal with.

Jennifer

[kwilford]

I just don't think it matters which side of the heater core gets the inlet flow, and which side it exits from. The only issue is how the valve functions with respect to flow direction. The OGTS diagram shows the flow into the side of the valve, exiting out the end. Here's the photo

[webster]

As per "FSM" look at pics

[webster]

And what it says - "FSM"
hope this takes care of it.
Webster

[jpiper]

Hey Graham;
I haven't had time to check the site for the last 2 weeks and now see that you have had some questions. Why not just give me a ring and come over to take a look under my hood? Leave a msg if there is no one home and I will gladly get back to you.

[bozkm]

I know this is an old post, but I have one quick question. Since I have replaced my solex with a weber with an electric choke..is it safe to say that I can remove the tees or should I just connect one tee to the other.

Thanks.

[nobody]

To cross the tees will put a bypass on your heater core. Eliminating them and doing new lines is the best idea.

[bozkm]

Thanks, thats what I thought also, then I got to thinking what happens when the heater valve is closed?? The water can't go anywhere, does the waterpump not need to suck it back when the therm opens? Crossing the tees is essentially operating the same way as if a water choke was in line correct?

[nobody]

Coolant circulates in the motor primarily and the heat for the heating core is just a small portion of it. Removing the tees is a common fix to lack of heat or poor circulation to the core. Romoving them is a simple fix to what was a pretty antiquated idea.

[kwilford]

Originally Posted by bozkm Thanks, that's what I thought also, then I got to thinking what happens when the heater valve is closed?? The water can't go anywhere, does the water pump not need to suck it back when the therm opens? Crossing the tees is essentially operating the same way as if a water choke was in line correct?

As David has mentioned, the coolant circulates around the engine even when the heater valve is closed and there is no coolant-heated choke actuator (for example, in later electric choke models), even when the thermostat is closed. There is a built-in bypass from the thermostat housing back to the water pump that allows flow around the engine. If the heater valve is open, the coolant also circulates through the heater core even before the thermostat is open. The choke heater only takes a small amount of coolant, relatively, but there is no need to allow that amount of flow if it is not required.

[WOOFS-OPEL]

What is the heater hose diameter on a GT - 5/8"?

[jvandyke]

Old thread but similar question. I can't tell exactly where the heater core hoses are supposed to come through the firewall???

[Anonymous D]

OMC Blitz (October 2006) issue Tech Tip, here:

Cooling System

(Vacuum hoses connections, are part of the
Tune Up Tech Tip, Part I, and are located
in the Engine Maintenance section of the
website).