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1968 Ford Mustang GTCS Cooling System

– thermostat, water pump and radiator

Hey alright today on Repairs101 I’ve got something really special for you – this 1968 Ford Mustang GT California Special I’m going to show you some handy tips and tricks on how to install the water pump, the thermostat and all the associated hoses and hardware.

Today’s episode of Repairs101 was made possible by Princess Auto. So when you’re a mechanic one thing you often encounter is a machine that’s already disassembled or partially disassembled when you get to it. Sometimes it can be a real challenge to put the puzzle back together but I always enjoyed puzzles.

One big puzzle

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In this case, the owner had carefully taken it all apart, meticulously organized all the replacement parts and was fully prepared to put it back together himself until I persuaded him to let me do it while he held my camera. “I actually made a video where I did this demonstration … but not everybody watches all my videos, so … you see I go in a figure eight pattern? You never do the same area twice like you would if you were doing this or going like that.” “Right” “And you see how much filth came off?” “No kidding.” “This will show you if you have any bad pits. And you don’t. A bit of a nick there but that’s it. Oh that’s not even a nick that’s just some stuff left over.”


So the thermostat is the brain of the cooling system and it’s nothing but an automatic valve that opens when a prescribed temperature is reached and closes again once it’s cooled off. You can see here that temperature is 195 degrees Fahrenheit or 91 degrees Celsius. You can apply “Room Temperature Vulcanizing” sealant to one or both sides of the gaskets used in this job but – you know what? If your flanges are straight you can install the gaskets dry and you won’t have any leaks. Be sure to get both of these bolts started before you try to seat either of them. I apply a thin layer all around the gasket and smooth it out with my finger to ensure complete coverage.

Water pump

The water pump is the heart of the cooling system. Start by mounting the three shortest bolts and then work on mounting the brackets for the alternator and the power steering pump before you torque it in a Star-Cross pattern, like you would torque the lug nuts on a wheel.

I strongly recommend a set of these hose pliers – they make light work out of removing even the hardest, crustiest baked on heater and bypass hoses. The bypass hose does exactly what it says it does. Trim it to fit using a box cutter with a new blade. Cut a little bit at a time. It’s better to have to cut it again than to buy another one. Lubricate with a drop of dish soap if it’s difficult to slide on. I found it works best to attach it to the thermostat housing first and then slide it on to the water pump outlet.

These clamps are old school and they work differently than the new style hose clamps. They’re kind of bulky so you might have to reposition them in order to make sure nothing touches anything that it shouldn’t.


The rest of this assembly is pretty straightforward – especially if you disassembled it yourself. I recommend “Never-Seez” on all the bolts and double triple check everything to make sure it’s all torqued down tight.

Let me know in the comments section if you think I should have included something about belt tensioning and maybe I’ll do a follow up video.

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Make sure you have the side air deflectors on hand as you lower the rad into place. You need to mount them with the same hardware. And you know, for sure this goes a lot easier if you can get some help.


Lower hoses will generally fit without any trimming. Just lube ‘em up, slide ‘em on and clamp ‘em down. For top hoses the distance may vary a little bit so they generally sell you one that’s a little bit long on the engine side. And, yeah, I did have to reposition those hose clamps to give a little clearance – because it’s tight! Use pipe dope on hydraulic fittings not silicone tape which can break down, get into the fluid and ultimately get into the pump and oh man that’s an expensive pump to have to replace.

Alright do yourself a favor and only use flare nut wrenches on flare nuts or you’re going to end up rounding the off and you’re not going to be able to open them without vise grips and you know, after you’ve done that, well, they’re just junk. “There we go. Oops. That was too tight. “

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Alright thanks for watching and don’t forget to subscribe and if you like today’s video please give it a thumbs up or leave a comment or better yet post it to your favorite social media site – Oh! I almost had it. I almost made it. (laughter) “Sorry.”

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