72 TCS solenoid ?

[Denny J.]

I have a loose wire not shure were it goes.It is the blue wire off the TCS going to the firewall and is connected to a green wire and that wire just hanges any help

[george romano]

Re: 72 TCS solenoid ?

The single green wire from the firewall harness has a plastic plug on the end. This is for a short (maybe 12"?) green wire pigtail that will plug into the temp sender on the rear PASS side cylinder head. This pigtail will have a double plug for the sender end, and a single plug for the harness end. Check the vendor catalogs for a picture.

Its purpose is to moniter the running temp of the engine so the TCS system will know whether or not to bypass the delay relay and send vacuum to the vacuum advance can on the distributor.

Clear as mud? I'm sure someone else can explain it further.

George

[Jack H.]

I'll take a stab...

The temp switch installed in the RH cylinder head has a single pole, double throw function. When the engine is cold, the temp switch is closed. This tells the TCS system to feed vac to the distributor to boost engine RPM and cause the engine to warm up rapidly.

When engine coolant temp hits the 'normal' operating range, the temp switch changes to its second position and becomes open circuit. Now, the TCS sytem provides vac to the distributor soley based on other considerations (what gear is the car in?).

The third position of the temp switch engages when engine coolant temperature climbs above the normal operating range and the switch closes. This forces distributor vac advance to raise engine RPM. This consideration of the system is a feature to thwart summer time, grid lock traffic, engine idle from causing overheating. With a slighty higher idle RPM, more air is pulled through the radiator to increase cooling.

A full description of how the TCS system works can be found in your copy of the 1972 Chassis Service Manual (Emission System)...

[Robert H.]

Been looking for

I've been looking for this very same temp swithch. Anyone know where to get one.

Thanks for any info.

[Patrick H.]

Re: Been looking for

You mean this one?

Any of the catalog vendors, and I'd bet you could find one at your local auto parts store.

Patrick

[Jack H.]

Why not call your local Chevy dealer? *NM*

[Patrick H.]

Been to one lately, Jack?

As Joe L has noted many times, if you visit your Chevy dealer then make sure you have the part number in hand. If they know how to find parts for a car prior to MY 2000 it's a surprise.

I find the counter people at NAPA and the local non-national chain auto parts store to be far more knowledgeable and helpful. They'll often let me look thru the big books with the pictures in them if I need to find a part and know what I'm after.

Patrick

[Joe L.]

Re: Been looking for

Bob-----

It depends what you want. If you want an absolutely original switch, then you need a GM #6489785. I don't know where to find one for sale.

If you want a functional replacement that 99% of the folks won't be able to discern from original, then you can pick up a GM #88924821, aka Delco #213-1141.

[Joe L.]

Re: Been to one lately, Jack?

Patrick-----

Yes, as soon as you say the part you want is for a 1972 model year vehicle, the word "discontinued" will usually "pass their lips" before they even know what part you want. A lot of these guys weren't even born when a 1972 car was built.

I have several interesting stories on this one. I used to purchase all my parts at a Chevrolet dealer in Hayward, CA. Since I placed about 2 or 3 orders there a week, ALL of the parts counter guys knew me by name. Of course, I always ordered all parts by part number so their dealings with me were pretty easy. Most of these guys were old-timers, too, not young kids.

I can't tell you how many times I was at the counter and some guy would come in looking for a part for an older Corvette. Even these old timers would tell the guy that it was discontinued without even looking. About half the time they were wrong; I KNEW that the part was still available. However, I kept my mouth shut since I didn't want to embarrass them. Now, keep in mind that this was in the 1970's and 1980's---some of the Corvettes that the customers were looking for parts for weren't even that old then.

I recall another time when I was looking for some of the parts that I needed to complete my collection of M-22 parts needed to fully assemble 1 transmission (the complete transmissions had already been discontinued by that time). Most of the parts were still available at that time but some were not. I purchased all the ones that were available from my dealer in Hayward. One that was not available was the case. However, the locater showed one in stock at a dealer in Costa Mesa, CA. So, I called them and asked if they actually had that part number in stock. Some younger sounding parts man checked his stock list and said that he had it but would go back and check the shelf to be sure. He came back and said that he had found it and then he said "... it looks like some sort of old transmission case for some old transmission...". I mean, he sounded like it was some ancient piece. Of course, I really didn't think of a Muncie as some old, ancient transmission and I figured that anyone ought to know what a Muncie case looks like at a glance. Well, this guy was probably in kindergarten when the last Muncie was installed in a passenger car. So, he didn't have a clue.

He sold it to me for a "bargain basement price" and I was happy as a clam. By the way, that case and all the other Muncie parts remained in 2 boxes in my closet for about 20 years before I finally assembled the transmission. It's in the car now.

[Patrick H.]

Re: Been to one lately, Jack?

20 years?
One of your shorter projects?

Just remember, the 69 has to be finished before the NCRS San Jose National Meet. And, if you get it done long before I'm still promising to come out and see it. I've seen it all in pieces. Now I need to see it done.

I'll let you drive to Monterey and I'll buy dinner.

Patrick

[Joe L.]

Re: Been to one lately, Jack?

Patrick-----

I hope to have it "virtually completed" by the end of this week.

[Patrick H.]

Re: Been to one lately, Jack?

"virtually completed"

That means it'll be in "virtual reality?"

Or...?

Keep me posted.

Patrick

[Gary Schisler]

Re: Been looking for

As Patrick says, these are very easy to find. I think I got mine for my 72 at Paragon but I know that the other catalog places have them. I suspect that something as benign as Advance Auto will even have them if GM doesn't.

Gary

[Jack H.]

Guess I'm spoiled...

One of the largest and oldest Chevy dealers in Denver (Burt Chevrolet) has 'crack' parts counter guys. If it's off the system, they go to the back room and load their reader with microfiche and look it up manually and VOLUNTEER to run the parts locator, Etc.

So, the answer to your question, Pat, is 'Yes'... But, there are good parts/dealers out there and then there are the 'quick transaction' folks who simply want to 'churn' customers for the easy to fill parts orders. Could be that's why Burt Chevy is one of the biggest crate engine dealers in the country...they care about service.

[Patrick H.]

Re: Guess I'm spoiled...

Ask Burt Chevrolet if they've ever sold a ZL-1 block to a guy in Hayward, California.



Patrick