thermostat

[mytsharpgn]

I am looking for step-by-step info on replacing the thermostat in my stock 87 GN. I have owned the car for 13 years and never replaced it.

It doesn't look easy, and my service manual is gigantic and not well organized. Anyone help here?

In addition, my passenger side valve cover does NOT have a PCV valve in it. Anywhere else it could be hiding? Thanks!!!!!

[PaCemkr86]

the PCV valve is on the passenger side of the intake manifold

[Keller]

...and should only be replaced with the factory part. AC P/N CV893C. Nothing else works correctly.

Back to cooling related things... The thermostat is easy to change, Back when I first started racing, I would change from the stock one to a 160F one in the pits when I arrived at the track, then back before I went home. (Hey, I was learning...) Its not that hard at all. Two bolts and that's pretty much it. Can leave the radiator hose attached if you wish.

[mytsharpgn]

OK, c'mon now. Could it really be that easy to replace? Keep in mind this car is stock, and the thermostat seems awful difficult to get to. In addition, I have heard that the stock neck is going to have to be replaced along with it. Is that the case? If so, it seems it would be easier clean up the inlet area if other things were removed to make it easier to get to.

As far as the PCV valve is concerned, I did locate it and replaced it with a stock one. Thanks!

[Ts86ttype]

Kellers' right, it's not that bad... Drain your coolant down, remove the flexable hose between the MAF and the turbo inlet, and you can even remove the two nuts holding the turbo inlet off and remove it for more clearence. Use an long extension and a 13 mm. wobblie and remove the bolt holding the retaining bracket on and it's just as easy to leave the upper hose on and grab hold and wiggle the stat housing out. Remove the stat and replace the o-ring on the stat housing, but some lube on the o-ring, install new stat and push the housing back into the manifold... It is easy, just take your time... Tom G.

[Keller]

The more stock it is, the easier it is. If you are still using a flex hose from the MAF to the turbo inlet, its even easier. The thermostat neck does NOT need to be replaced. It may need a bit of encouragement to be removed the first time if its never been out before or recently. And it needs to be lubed when its being replaced.

If you are not a frequent user of tools, keep a magnetic pickup tool handy. Just in case... Other than that, it really is a piece of cake. If was a PITA, we would tell you.

[PaCemkr86]

If you are wanting a new style thermostat housing , here they are.. Not really needed unless your factory one is all corroded..

http://www.gbodyparts.com/product_info.php?products_id=477&osCsid=9503580f1b87734a46ad0735b43b0462

https://www.gbodyparts.com/images/buickthermostathousing.jpg

i also sprung for the new billet hold down..

http://www.gbodyparts.com/product_info.php?products_id=816&osCsid=9503580f1b87734a46ad0735b43b0462

[IL KIM]

...and should only be replaced with the factory part. AC P/N CV893C. Nothing else works correctly.

Scott, can you elaborate on this? I just bought a non-AC part and was going to change mine out today... I can return it though - haven't opened it yet.

[PaCemkr86]

the correct ac/delco pcv valve, is setup for boosted applications and will not pressurize your crank case etc..

[Keller]

What he said. :brows:

Every other manufacturer has their part cross-referenced to other cars. That is simply not possible. Especially if they are normally aspirated cars. Yeas of seeing people struggle with poor idle and such leading back to the PCV being non-OEM has led me to campaign for use of the stock one. Have never heard of anyone having an issue with the OEM ones.

So, get the right part and keep a spare handy.

Now, back to cooling system chat, please...

[mytsharpgn]

OK. Got everything apart. The thermostat housing was a bit of a PITA to get out, but it came out. It was a bit corroded, and since Phil was nice enough to provided a link for a new billet housing, I decided to order it, along with a thermostat, because the one from my local auto parts store was the wrong size. Thanks Phil.

As part of removal process, I also removed the pipe that goes from the intercooler to the throttlebody. I noticed along the lip of the intercooler pipe was very small pool of oil. I'm thinking there shouldn't be oil sitting there. Do I need to be concerned? The intercooler has never been through a spring cleaning.

Thanks.

Kirk.

[PaCemkr86]

your welcome.. are still running the factory turbocharger ?

[mytsharpgn]

Yes. Factory turbo. In fact, everything is factory except for the K&N drop-in filter and Hooker exhaust.

[PaCemkr86]

time for some spring cleaning..

[mytsharpgn]

So, you're saying it's time to clean the intercooler? :idea:

I don't need to be worried about the oil? Do you have an idea where it came from?

[Keller]

Is the tube from the passenger's valve cover still connected to the turbo inlet bell?

If so, oil can be sucked in through there. If not, a small amount of blow-by is not unusual.

[mytsharpgn]

OK. Got my parts today, and I had ordered an upper radiator hose from OReilly Auto Parts. Went to pick up the hose, and this guy brings out a straight flexible hose. Yeah, that's not gonna work. So I call Arnold Motor Supply. Guy said neither his computer nor his parts book have a part number. Head to a local AC-Delco parts store. Guy there asked what size motor was in my Grand National? :nope: He gives me a Dayco part number that he says he could order for me. I told him I'd check back. Head down to Napa. Find out the Dayco number from the previous guy crosses to the non-turbo motor. Nice. But nope. Napa only can get the flexible hose. Last chance is Advance Auto Parts. Guy says he can get it, and have it tomorrow. I asked to see a picture, and it sure did look closer to the correct hose than anything I'd seen so far. Surprised they're open on the 4th, so we'll see what shows up for $7.34.

Had no idea these hoses were so hard to get. If this doesn't pan out, I'll go back to the AC Delco store with the part number from this website and see if he can get it this time. If not, I guess it's GMpartsdirect.com, unless anyone has any less-expensive options ($35 with s/h).

[PaCemkr86]

here ya go bud

http://www.nos4gn.com/servlet/the-Cooling/Categories

[Keller]

FWIW, I'm pretty certain that Gates makes the correct hose as well. It will always be a special order part.

O'Reilly carries Gates, as I recall.

[mytsharpgn]

Well, if Gates makes the correct hose, it seems that nobody here can locate it or cross-reference to it from the GM part number. I've always known Gates to make quality belts & hoses. We'll see what shows up tomorrow.

[Keller]

Here's what I've found before:

http://www.gnttype.org/forums/showthread.php?t=6393&highlight=radiator+hose+upper

Any Advance/Checker/Kragen/Schucks and maybe Murrays might be able to get the Drive-Rite line.

[Keller]

Last chance is Advance Auto Parts. Guy says he can get it, and have it tomorrow. I asked to see a picture, and it sure did look closer to the correct hose than anything I'd seen so far. Surprised they're open on the 4th, so we'll see what shows up for $7.34.
Check the link I just posted. Price now showing $9.34 retail online. Interesting that it is cheaper despite a weak dollar a year or more later. Be interesting to see if its still made in Mexico or if its gone overseas.

[mytsharpgn]

Yeah, I may have been reading the screen wrong at the counter yesterday. It might be $9.34. But it is the same picture I saw in the store. Interesting that the part number (less the E) matches the Dayco part number I got from the AC Delco store, which the Napa guy told me crosses to the N/A V6.

[Keller]

Good info to know.

As you've seen, the N/A V6 and the 86/87 V6 app do require a different hose.

[mytsharpgn]

OK. Returned from Advance Auto Parts. It is an EXACT match to what I had, it is still made in Mexico, and it IS $7.34!!!!!!!

Heading out to put everything back together. Thanks for all your advice!!!! I will be back later for more questions on other things I want to fix.

BTW, now that I have it apart, why didn't GM design all their engines with this style thermostat and neck? It is MUCH easier to work with than the traditional design. No gasket, one bolt, no sanding and scraping of the old gasket to ensure a proper fit. It's actually quite ingenius.

Kirk.