Cooling System, low temp CAB heat now

Tiny
JBUCO315
  • MEMBER
  • 1995 BUICK ROADMASTER
  • 5.7L
  • V8
  • RWD
  • AUTOMATIC
  • 58,000 MILES
Hello, I recently decided to change the antifreeze in my vehicle. Aside from it being the original Dexcool, 19 years old with 58K, nothing was wrong with the system or its operation! I drained the radiator and then disconnected all the hoses, drained them and then ran water through the system, from a hose, AT LOW PRESSURE until all ran clear. I did not pull the knock sensors, I tried but I was not able to get a good enough bite on them with what I had available. I then replaced the thermostat with a new one, factory 180 degree.
Now, I put it all back together, I did like the books say, I filled the reservoir with fluid, started it, and bleed it once the temp got to the temp to open the thermostat (with the reservoir cap off). *This is where the issues start. Yes air bubbles come/came out the bleed screw and while that is happening, the reservoir starts filling to the top and starts "spitting" and overflowing, every time! I turn it off and it quickly draws the fluid back in, sometimes all the way down/dry. I let it cool off, add some fluid, and it happens all over again. I have one of those no spill funnels so I put that on there. It backed up into there, and went up and down again. Thinking many things, I also checked the heat coming from the vents. I have it on it's hottest setting. The temp there fluctuates right around 100 degrees, (this has the digital climate control, and I have it in diagnostic mode to read engine temp) with the engine at 195 degrees. At 197 the coolant fan kicks in and temp drops back down to around 180 range. I have been noticing that right around 195 is where the level in the reservoir starts "spitting" and coming up. I got frustrated and let it cool off overnight. Next morning I drained the radiator again just by it drain spout, and refilled the system. Same thing again, barely any heat and it keeps pushing the fluid out or the reservoir. Trying something different, I replace the thermostat with another new one, and refilled the system. SAME THING AGAIN!
To me the stat is opening and system fans and sensors seem to be working fine, why can't I get the heat I used to have? Why does it seem to keep bubbling over? FYI: I capped it off this last time, watched the temp and using a flashlight, watched the level in the reservoir when it got close to 197, I cracked the cap, I could see the level start to spit and rise, usually by this point the fan would kick in, before it overflowed I tightened the cap, the fans cooled it down to the lower 180's and the level would drop back down.
So, I let it cool capped it off and have been driving it. Unless I am sitting in my driveway, for a while, under normal driving It never gets above 177 anyway, outside temp in 50's, city driving with occasional 3-4 miles on hwy. Starting to wish I had never touched it!
Do you
have the same problem?
Yes
No
Sunday, December 6th, 2015 AT 5:17 PM

4 Replies

Tiny
ASEMASTER6371
  • EXPERT
The easiest way to get the air out is to remove the thermostat again. With it out fill the cooling system until the coolant is at the top of the intake where the thermostat goes. Install the thermostat and top off. Then run the motor with the cap on and the tank full to get rid of the rest of the air.

Roy
Was this
answer
helpful?
Yes
No
Sunday, December 6th, 2015 AT 6:53 PM
Tiny
JBUCO315
  • MEMBER
Great, will re-do and let you know. Thanks, John.
Was this
answer
helpful?
Yes
No
Monday, December 7th, 2015 AT 8:17 PM
Tiny
JBUCO315
  • MEMBER
Okay, it is finally done. FYI in my haste, when changing the coolant the first time, I drained and flushed everything but the reservoir. Well, that turned out to be where the problem was. This particular models tank is all subdivided on the inside and it really holds coolant. The car set a lot over the years and the Dex-cool sludged up. When I refilled the reservoir the first time and let it draw the coolant into the system, it pulled a lot of the sludge as well and had clogged up the heater core. After many many flushing's of the whole system, it now works like a dream! I have an aftermarket bleed valve with a nipple on the water neck, but it seems to allow air into hose when I am trying to bleed, but I think I have it. If there is still a little air in there, will it eventually cycle it into the reservoir and/or purge it on its own? Thanks again for everything.
Was this
answer
helpful?
Yes
No
Saturday, December 12th, 2015 AT 9:15 PM
Tiny
JBUCO315
  • MEMBER
Oh and yes, I did pull the knock sensors this time as well.
Was this
answer
helpful?
Yes
No
Saturday, December 12th, 2015 AT 9:16 PM

Please login or register to post a reply.

Recommended Guides