Volvo RWD 700 Forum

INDEX FOR 10/2025(CURRENT) INDEX FOR 7/2016 700 INDEX

[<<]  [>>]


THREADED THREADED EXPANDED FLAT PRINT ALL
MESSAGES IN THIS THREAD




  REPLY TO THIS MESSAGE    PRINT   SAVE 

Overheating while idling? 700

posted by  Rtilghman on  Tue Mar 9 10:34 CST 2004
Author: [PROFILE] [EVERY POST] [THREADS] [BEST POSTS] RSS Feed     [IGNORE ALL POSTS] [RELATED]

1985 745t

Went out and started the car this morning before going to the office. I let it idle while I finished up in the house, then went out to get going. However, when I got in I saw that the needle for the temp gauge was up JUST below the red zone, say a few cm off or so.

I sat in the car for a couple minutes and moved the car a litle bit on the driveway, but the needle just sat way up there. I opened the hood and felt the radiator and it was fairly cold to the touch. I felt the valve cover and it was hot. I felt the hose from the radiator to the t-stat housing and it was warmish at the radiator side, hot at the t-stat side.

I decided to start driving and see what would happen. Lo and behold as I started driving the temperature gauge dropped, eventually dropping all the way down to its normal "initial" operating positing of a couple cm off the bottom of the gauge. However, I wasn't going nearly fast enough (10-20mph) for any noticeable difference regarding airflow over the radiator. So I figured it was just a wierd fluke or something, but when I drove home I stopped in the driveway and the same thing happened in reverse! The gauge slowly started climbing up until it was around the halfway mark. At the same time the heat coming out of the blower/heater disappeared, and I started getting only cold air inside.

Now I know my cooling system needs work and can be funky. Generally when I start the car the coolant temperature will rise to 2/3 and then drop when the t-stat opens. However, this problem just kind of has me boggled. My car is an early model brick, so it doesn't have an aux fan requirement to run or anything. It's also still cold outside (like 30f today), so I wouldn't expect this kind of overheating to occur. Finally I would normally guess a faulty heater valve for the disappearing heat at teh dash, but the ABRUPT change in temperature occured in like five seconds, and that seems to quick to lose all the heat in the core.

So what should I look at? Is it possible I have a faulty valve, that I'm losing vacuum at idle and that the valve is allowing coolant to quickly evacuate the core but not to refill it? Why would that cause my coolant to start heating up at idle though? Shouldn't the brick be able to handle normal idle heat without the surface area of the core?

Sorry for the long post but I wanted to be thorough. Thanks in advance for any help.

Best,
Rick








  •   REPLY TO THIS MESSAGE    PRINT   SAVE 

    Overheating while idling? 700

    posted by  Aye Roll on  Tue Mar 9 13:19 CST 2004
    Author: [PROFILE] [EVERY POST] [THREADS] [BEST POSTS] RSS Feed     [IGNORE ALL POSTS]
    last visit: Tue Oct 14 21:08 CST 2014
    [RELATED]

    Rick-
    sounds like it's jsut low on coolant. you're sure the level is good? One of mine has such a dirty coolant reservoir that I have to take the cap off to check.
    The car ought to have good heat if the fluid is full but the thermostat is stuck. I guess if the t-stat is failed open, then it could be just getting too cold, but that's not consistent with the heat gauge going high- the one case recently of a stuck (broken in half actually) thermostat that I saw, the engine was not warming up.

    Check that level, and check closely for leaks. Good luck with it!
    --
    Rob Bareiss, New London CT ::: '87 244DL/M47- 225K, 88 744GLE- 209K, 91 244 183K. Also responsible for the care and feeding of: 88 745GLE, 229K, 88 244GL, 146K, 87 244DL, 235K, 88 245DL, 236K








  •   REPLY TO THIS MESSAGE    PRINT   SAVE 

    Overheating while idling? 700

    posted by  aleekat on  Tue Mar 9 11:01 CST 2004
    Author: [PROFILE] [EVERY POST] [THREADS] [BEST POSTS] RSS Feed     [IGNORE ALL POSTS]
    last visit: Fri Oct 24 13:19 CST 2014
    [RELATED]

    Rick, I have an 85 740 na. I have an aux fan(factory). Did you remove yours?








    •   REPLY TO THIS MESSAGE    PRINT   SAVE 

      Overheating while idling? 700

      posted by  Rtilghman on  Tue Mar 9 11:07 CST 2004
      Author: [PROFILE] [EVERY POST] [THREADS] [BEST POSTS] RSS Feed     [IGNORE ALL POSTS] [RELATED]


      I replaced a near frozen aux fan on my brick a few years back. The unit on the car has been fully tested by jumping it straight to the battery, and it works fine.

      However, I shouldn't even need teh aux fan on my 1985. The aux fan on teh eartlier models is just an emergency back-up to avoid catastrophic damage... it doesn't even trigger until like 210f.

      Thanks,
      rt








  •   REPLY TO THIS MESSAGE    PRINT   SAVE 

    Overheating while idling? 700

    posted by  Bexar Wires on  Tue Mar 9 10:47 CST 2004
    Author: [PROFILE] [EVERY POST] [THREADS] [BEST POSTS] RSS Feed     [IGNORE ALL POSTS] [RELATED]

    Rick,
    It sounds like your thermostat is sticking. Very easy to replace. Two nuts hold the t-stat housing to the head. Be sure to clean both surfaces and the groove in the housing. Flush out the old coolant and replace with new, 50/50 mixture of anti-freeze and water (if you have hard tap water where you are, use filtered or bottle water).
    Good luck.
    Rick







<< < > >>



©Jarrod Stenberg 1997-2022. All material except where indicated.


All participants agree to these terms.

Brickboard.com is not affiliated with nor sponsored by AB Volvo, Volvo Car Corporation, Volvo Cars of North America, Inc. or Ford Motor Company. Brickboard.com is a Volvo owner/enthusiast site, similar to a club, and does not intend to pose as an official Volvo site. The official Volvo site can be found here.