View Full Version : Removing the Heater

04-14-2005, 05:06 AM
I can't believe it's come to that. But in my TR4A I need to re-wrap the wiring harness and the heater is in the way.

Question: Is it as messy as one would suspect? With 40 year old rusty water spilling over everything?

Mickey Richaud
04-14-2005, 09:36 AM
Hey, Kentville -

It's messy, but you might try this:

Instead of disconnecting the hoses (probably rusted to be one with the outlet tubes anyway), cut them at a place where you can put a pan or bowl to catch most of the water. You'll want to replace the hoses, anyway, and then plug the ends.

Also, you might try disconnecting the hose at the heater control valve on the head, and siphoning off as much water as you can before you cut the hoses and pull the heater.

Good luck, and let us know how it goes.


04-15-2005, 07:04 AM
Disconnet both hoses and drain off as much coolent as possible, then tie a rag around the end of one hose and apply compressed air through the other to blow off excess coolent.

Geo Hahn
04-15-2005, 02:42 PM
If that is a suggestion to blow compressed air into the heater core I would suggest you use very low pressure and great care. The core is normally subjected to no more than 7 psi and compressed air or even a garden hose can be too much for it.

Gee KVH - I was almost ready to volunteer to lend a hand with your '4A harness until you got into the messy stuff.

Not to tempt you, but my '4 has no heater and although I might miss it a little on early morning drives in the winter that sure makes other maintenance much simpler.

04-15-2005, 05:14 PM

You can reduce the mess a little by draining the cooling system as completely as possible first, via the petcock on the bottom of the radiator and the one on the side of the engine block (roughly below the heater control valve, about half the distance to the starter).

Alternatively, just remove the large radiator hose at the bottom of the rad.

In fact, getting a high rate of flow out of this bottom hose might act a little like a siphon and suck more of the coolant out of the entire system. Leave the rad cap on initially and be sure the heater valve is open. Pull loose the hose, and let it flow.

Next remove the heater hoses inside the engine compartment, before those inside the car.

The above procedure won't remove all the coolant from the heater, but will reduce the total amount a bit. I agree with cutting the interior hoses (have your replacments onhand first).

While everything else is apart, you might optionally want to remove the heater control valve and the pipe that comes from the water pump housing along the LH side of the engine for inspection and cleaning. The bulkhead fitting, where the heater hoses attach at the firewall, are prone to rusting and might need replacement, too.

I also feel it's dangerous to use compressed air to force coolant out of the system. There is simply too much danger of doing a lot of damage to a system that basically operates on very low pressure. Damage could be done to the head gasket, the figure 8 seals on the bottom of the liners, the radiator or heater cores, or any other seals in the system. Some of these possibilities could require an engine rebuild to correct. Too risky for me!



04-18-2005, 03:35 AM
I'm getting there, slowly. Wiring harness is almost ready to re-wrap. Just about four feet of it. I finally found the original non adhesive black tape. Two or three weeks and I should be back on the road. Too bad I'll miss this great weather.

04-18-2005, 03:38 AM
OOPS, forget to mention: Thx for all the advice. I cut the hoses first and made very little mess. Ugly brown water came out of the heater, then I flushed it with tap water. Then I primed and re-painted the heater housing, sparing the decals, of course. Fingers crossed it won't now leak.