When easy jobs go horribly wrong...

[Big Black Beast]

After a cold start, the temp gauge has been going all the way to the top before it finally suddenly drops down to normal, then stays there. Probably the thermostat.

Failure 1: After dousing the crossover plug with liquid wrench and banging on it a bit, I put a socket in the square hole and go to loosen it. That was easy, oh wait, of course not, the square hole rounded out and it's stuck tight.

Failure2: Attempt to change thermostat anyway, housing bolt head strips.

Now what? Can I just replace the whole housing? The only part I can find is RH70 and it only looks like the upper half, unless I'm missing something. And is the crossover available? How do you replace it? It just looks sort of stuck in there? I'll check w/ the dealership tomorrow, any help and ideas are greatly appreciated.

[Mr. Man]

Be prepared to clutch at your heart when you here the price of a cross-over tube.

[Big Black Beast]

If I can get the thing, I will be happy. I need to get to work here somehow and need to get it fixed before the thing sticks closed completely. Everything's a disaster right now, and this on top of it, I did not need.

[Mr. Man]

I checked on the cross-over tube about 6-7 months ago and they were still available. Ours was flaking paint and I thought to get one and powder coat it till I heard the price. New plan became repaint the old one.

[Big Black Beast]

Okay, what was the price? Quit the vague hinting. I need to know what I'm in for.

[fastblackmerc]

Okay, what was the price? Quit the vague hinting. I need to know what I'm in for.

Call your local dealer or check online.

BTW.... you should be able to get the plug out with some vise grips.

[musclemerc]

^^^ +1. The first time the plug is removed you have to use vice grips to get it off.

[69marquis conv]

I rounded out the plug on the crossover tube on a Cobra I had several years ago. I used a hacksaw to cut a groove across the top of the plug then gently tapped the groove in the left-handed direction to unscrew the plug with a wide blade screwdriver and a hammer.

[Mike]

After a cold start, the temp gauge has been going all the way to the top before it finally suddenly drops down to normal, then stays there. Probably the thermostat.

Failure 1: After dousing the crossover plug with liquid wrench and banging on it a bit, I put a socket in the square hole and go to loosen it. That was easy, oh wait, of course not, the square hole rounded out and it's stuck tight.

Failure2: Attempt to change thermostat anyway, housing bolt head strips.

Now what? Can I just replace the whole housing? The only part I can find is RH70 and it only looks like the upper half, unless I'm missing something. And is the crossover available? How do you replace it? It just looks sort of stuck in there? I'll check w/ the dealership tomorrow, any help and ideas are greatly appreciated.

http://www.mercurymarauder.net/forums/showthread.php?t=66644

Here's a crossover tube for sale

[babbage]

Heat up the crossover plug first - then it will come right out - no rounding.
(use a propane torch - not the engine to heat it up a bit first)

How did you strip the housing bolt head? Just get a dremel and cut the bolt head off or make a notch in it.

Just drive your car to the dealer and let them fix it.

[burt ragio]

Chances are all you needed was to burp & add coolant fluid elevate front of car apx 8"durring process. Let PB Blaster sit for recomended time. Use channel locks to remove filler cap. Remove thermostate housing redrill & tap.

[Blackened300a]

Chances are all you needed was to burp & add coolant fluid elevate front of car apx 8"durring process. Let PB Blaster sit for recomended time. Use channel locks to remove filler cap. Remove thermostate housing redrill & tap.

I agree, thats air in the system. The other option to getting the plug out was welding a nut to the top and use a wrench.

[bugsyc]

It may be your thermostat BUT, I had the same problem..guage went all the way up before it fell (rapidly) to half way..took it to the dealer..he said it was a coil..and they needed to run a 8 hour test. I said themostat,he said they tested it and it was opening and closing properly... anyway, my aftermarket warranty wouldn't cover the test until it was proven that coil interference was the culprit...about $1200 all told.1 coil replaced...I was left paying about $200....worked for 3 or 4 days and back to before....I let it go....when I installed Lidio's tune,the problem went away..guage works...needle is half way....that was my experience...;..hope you have better luck...

[Big Black Beast]

Update, Well, apparently banging on the thermostat housing freed it up, as it is working normally now. Thanks for all the suggestions. I actually tried vicegrips, but they just chipped off a portion of the cap. I didn't have any power tools last night so I may try grinding a slot this weekend. Yeah, if I ever get it off, i"m gonna weld a nut to it.

[Marauderjack]

I've had the same "FUN" with that damn plug and wondered why anyone would tighten it so tight??:confused:

It has an "O" ring on it and finger tight is adequate......I've found!!:beer:

[fastblackmerc]

I've had the same "FUN" with that damn plug and wondered why anyone would tighten it so tight??:confused:

It has an "O" ring on it and finger tight is adequate......I've found!!:beer:

I put a small amount of anti-seize on mine before snugging it up.

[Marauderjack]

I use Dow Hi-Temp silicone grease.....but any lubricant in the threads is OK!!:D

[Big Black Beast]

Update. Car is fixed and works fine now. Vise grips+hammer+high temp RTV saved the day. I would like to have a word with the jerk that invented those factory hose clamps though...