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Discussion Starter · #1 ·
Hi All.

I'm a new member here and wanted to list what vehicle I have. I bought a 1994 Roadmaster Limited about a month or so ago from a retired guy. It has 87,000 miles on it (was mostly registered and driven in florida per title since '94) and seems to be running pretty well so far.

Here is what I have done so far:

1.) Replaced original thermostat with another stock 180 degrees.
2.) Flushed cooling system
3.) Replaed coolant temp sensor
4.) Replaced both primary and secondary cooling fan switches in fuse box under hood (since I thought car was overheating due to temp gague reading near hot, but through reading I am thinking this is normal with stock thermostat).
5.) Buick dealership found faulty temp gague for cluster and replaced, but needle still goes high when a/c is off, but primary fan kicks on when almost in red on temp gague on dash.
6.) Replaced air filter
7.) Can't seem to locate PCV to inspect (not in valve cover).

Will post ya'll some pics of the vehicle soon. Other than what I have done so far, what do you guys look for typically when you buy a used car like one of these? This is my first Buick vehicle.
 

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These cars can get that hot before the primary fan turns on (229 degrees). GM programmed the pcm that way. You can verify actual temperature using the digital climate control. My car would never go past the half mark when I had the mechanical fan. The fans never had to turn on. However, when I converted the car to dual electric fans, the temp would just keep rising past the half mark (while sitting). I never let it sit long enough for the fans to turn on but, it did get past the 3/4 mark.

A few weeks after the conversion I installed a 160 t-stat which helped a lot. The temps would still rise but at a slower pace. Also, cruise temps fell tremendously. I would force the primary fan to activate by turning on the A/C if I was sitting in traffic too long. A few weeks ago, I got the pcm tuned to turn the fans on earlier. The temp gauge sits around the 1/4 mark or a little higher in stop and go traffic. I don't like how hot these cars get before the fans activate.
 

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Discussion Starter · #7 ·
Nick, thanks for the picture. I went to advance auto a few weeks ago and bought a PCV valve, but there were two types available per their computer (1 that would typically sit in a rubber grommet and another that had threading like a sensor). If I am looking at your picture correctly, the PCV valve is the silver cylindrical thing attached to the rubber tubing... right? I want to be sure i purchased the right one.

Thanks!
 

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Discussion Starter · #8 ·
Heavy, in order to "tune" the pcm to turn on the primary fan sooner, does this require the lower temp thermostat? I don't like that the engine gets so warm before the fan comes on either. It's not much to worry about now since it is summer and I'm using the ac, but come winter it seems like it would be more of an issue.
 

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Nick, thanks for the picture. I went to advance auto a few weeks ago and bought a PCV valve, but there were two types available per their computer (1 that would typically sit in a rubber grommet and another that had threading like a sensor). If I am looking at your picture correctly, the PCV valve is the silver cylindrical thing attached to the rubber tubing... right? I want to be sure i purchased the right one.

Thanks!
The PCV valve looks a lot like a dashboard cigarette lighter. No threads. It's just a tube where one end plugs into the grommet, and the other end into a rubber hose.

You'll have to wait until someone more expert than me joins the thread to tell us definitively, but I think that the LT1 is designed to run warmer than other engines.
 

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Heavy, in order to "tune" the pcm to turn on the primary fan sooner, does this require the lower temp thermostat? I don't like that the engine gets so warm before the fan comes on either. It's not much to worry about now since it is summer and I'm using the ac, but come winter it seems like it would be more of an issue.
The stock settings are too high IMO. You could have the settings changed without the lower degree t-stat. The stock primary fan turns on at a 229 degrees and the secondary is on at 234 degrees! Even having the primary fan turn on at around 205 degrees will make a big difference in performance and gauge position. Your best bet is to talk to one of the well known LT1 tuners for their opinion on the lower turn on temps with the stock t-stat.
 

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Discussion Starter · #11 ·
So, I replaced the PCV valve tonight. What a PITA part to access. The rubber tubing that the pcv was attached to was so hard I had to go to the store and get another piece. I didnt realize that the pcv connecting hose is actually metal...interesting! Once I got the home plate piece off the top, I saw some other small vacuum line connections on the opposite side of the plenum that needed to be replaced, some were cracked and falling apart. Easy fix though.
 
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