Fixed my overheating problems (88 RS/2.8 V6)
 

I think my overheating problems are finally fixed. Here's the story:

I bought this car (an 88 RS with 2.8 V6 and T-5 trans) as a parts runner/grocery getter cheap from a storage auction. It was advertised as having 90k miles on it. Well, it had 100k more than that. The radiator was junk (big crack in the plastic end cap) and there were about 100 more little problems.

The biggest problem was overheating. I couldn't get it to run anywhere near a reasonable operating temperature no matter what I did until I hit the magic combination:

1. I removed the thermostat. (I did this so I could flush the cooling system without any flow restriction.)

2. I installed an aftermarket temperature gauge to replace the POS in the instrument cluster that never gave me consistent readings.

3. I installed a manual switch for the fan. There's something strange going on with this and it may be a tired fan, but I can't just leave it in the ON position and start the car. I have to start it, then switch the fan on and make sure I see a drop on the volt gauge indicating that it's on. I think this is one of the biggest improvements. Whoever decided to turn the fan on at 220 was smokin some heavy stuff. For reference, I used a piggy-back connector on the Grn/Wht wire in the connector to the middle of the 3 relays on the firewall between the master cylinder and the fender. Then I installed a switch with the other wire running to ground. I'll mount this switch permanently in the panel below the cigarette lighter.

4. I flushed the system (twice) with the chemical flush solution (I used 2 bottles, one at a time) and backflushed the system using a connection in the heater hose. I didn't see much junk coming out of the radiator as I was doing this, but it may have been dissolved and not easily visible. Funny thing: I never saw any rust-colored anything come out of the cooling system. I expected quite a bit of rust from a 200k block, but the only thing I saw was some cloudy substance as I began the backflush.

I tested this last night with a long drive in city and highway driving, with speeds ranging from 20 to 80 mph in 90 degree weather. The hottest temp I saw was about 185 after a couple of miles at 80. When I exited the freeway, the temp dropped to 160. I still have the flush chemical in the system, but when I flush it out, I'll install a 180 thermostat with bypass holes drilled in it.

I feel like a big burden has been lifted from me, since I've been fighting this problem for a couple of weeks. I hope this writeup can help someone fighting the same problem.

RtR
http://www.chevyasylum.com

Re: Fixed my overheating problems (88 RS/2.8 V6)
 

Update: I installed a thermostat that was supposedly a 180F...I tested it using the stovetop heating thing. It read more like a 195. So I got another 180 from a different vender (although they looked like they'd been made by the same vendor in Won Hung Lo province in China) and it ALSO opened between 190 and 200. Yet I tested a t-stat marked 195 and I couldn't get it to open on my stove. I live at 4300 ft altitude and water boils at 204 here. The thermometer I was using seemed to indicate the correct water temperature. Beats me.

Anyway, I installed the one marked 180 with 4 0.015" holes drilled in it and the car now runs consistently at an indicated (aftermarket mechanical gauge) 190F even in 99.5F ambient temps (it's hot with a black interior and without A/C). I'm happy with that. Now I'm moving on to the next problem, a transmission mount I thought I'd fixed. Two steps forward and 1.5 back.

RtR
http://www.chevyasylum.com

Re: Fixed my overheating problems (88 RS/2.8 V6)
 

Ray that is great! I had the same problem and flushed the Rad, and bought a Airdam. Fixed the problem! Now my car has a lot of pressure in gas tank causing it to smell of gas and choke, sputter and die until it cools off. Mystery to me and many others on the forum. I have the same motor as you, do you have any ideas, thanks

Re: Fixed my overheating problems (88 RS/2.8 V6)
 

I'm not positive about 3rd gen F-bods, but other GM series (particularly G-bods, with which I'm more familiar) use a return line from fuel pump to the tank (they're mechanical pumps) and a 3rd line with is the vapor recovery line that leads to a charcoal canister. I just went out and looked at the Camaro and it has one of those delightful ECM controlled canisters, probably with purge cycle, etc. I'd wager that's where your problem lies.

The old solution used to be to poke a vent hole in the gas cap. That's before the EPA decided they knew how to build better cars than the manufacturers.

Anyway, here's what I did on the Monte Carlo I'm preparing to run on the salt flats in a coupla weeks:

http://www.target550.com/temp/85Monte-950r8.jpg

I've removed all the emissions stuff from the car, but kept the original fuel tank and its vent line. That white plastic cylinder thing is a fuel filter. I've connected one end of it to the vent line and the other end is left open to the atmosphere. Emissions-happy people probably don't like that, but it does a coupla things. It prevents the low pressure situation in the tank, which will cause a car to run like crap and it keeps cooties from crawling back up the vent line. There's some gasoline odor from time to time, but no more than what you'd have with a vented gas cap...less, actually, since the only time the pressure flow goes from the tank out thru the filter is if the temperature of the fuel in the tank rises enough to cause it to expand and force vapor out. The rest of the time, the air flow goes in the opposite direction to allow air in to compensate for the gas flowing out thru the pump.

I hope this works for ya and alleviates your problems. Btw, here's the story on that Monte Carlo:
http://www.chevyasylum.com/85monte/Welcome.html and here are some photos I did of Speed Week a coupla weeks ago:
http://www.chevyasylum.com/lsr/bsf20...x/Welcome.html

RtR
http://www.chevyasylum.com

ps. I'm thinkin about pullin the V6 and 5-speed, adding a turbocharger and installing it in a 2nd gen Camaro cuz the Land Speed Record was just set at Speed Week at a screaming 32 mph. That's right, the F/CBFALT record was set by David Freiberger (editor of Hot Rod Magazine) running his 2nd gen Camaro on 2 cylinders. He didn't intend it that way, but after the first pass he made killed the motor, cylinders 1 and 6 were all they could resurrect. So they entered it int the "F" engine size class (2.0 to 3.0L) and limped to a 32 MPH record after getting a hell of a lotta help from the push truck.
http://www.chevyasylum.com/lsr/bsf20...110r8_jpg.html

Ohh...I've got the makins of a killer 406 smallblock that might replace the 2.9 in the 88. All I'd need is a T-56 tranny and all the other driveline goodies. :)

Re: Fixed my overheating problems (88 RS/2.8 V6)
 

Glad you fixed your overheating problem. The only time my car starts to overheat is when im idling for long periods of time, and it's because my radiator fans dont come on. Any suggestions on how to get them to work?? I already have a switch but i need ideas on how to run the wiring and what kind of wire and everything else. Please help. Thanks!

Re: Fixed my overheating problems (88 RS/2.8 V6)
 

Without any sarcasm or malice, I'll ask, "Did you read item 3 in my list of things done?" That tells you exactly where I ran the wire to the switch for the fan and it alludes to the fact that the ECU turns the fan on a 220F...which, in my experience, is WAY too hot. I know, emissions crap and all that, but it's still too frikkin hot. 180-190 seems to be the best operating temperature for conventional water-cooled motors. Just my opinion, but I've been building smallblocks for a long time and that's where they run the best...and I know the 60V6 isn't a smallblock, but it has a whole lot in common from a theoretical standpoint.

Anyway, as I wrote, the engineers that decided to turn the fan on a 220 were smokin some real heavy stuff. Not that I ever did any of that back in the 60s, but they say that if you can't remember the 60s you must have been there....I think.

So. Read that first section and it'll tell you how I installed a manual switch for the fan. I spose you could get a different fan controller from Derale or Painless or Dakota Digital, but this way's quick and dirty.