Overheating on the highway, but not in the city

+ Reply to Thread
Page 1 of 2 1 2 LastLast
Results 1 to 25 of 45

Thread: Overheating on the highway, but not in the city

  1. #1
    SupraForums Member Esvilopez's Avatar
    Join Date
    Jun 2007
    Location
    Rhode Island
    Posts
    289

    Overheating on the highway, but not in the city

    Hi guys I have a problem with my car, i was driving today and the temperature started to go up I pulled over and the temperature went down I drove it for about 20 min, in the city and the temperature was less than half, I took for a ride again in the highway and the temperature started to go up what could be I'm thinking is the fan clutch I have a brand new thermostat and mishimoto radiator.. also when it was hot the coolant was coming out of the overflow tank. Any advices will be appreciated,

    Esvi.

    95 Supra TT Hard Top.SOLD
    1988 RX7.
    2005 Escalade.
    98 Chevy Silverado.
    92 Subaru SVX AWD

  2. Remove Advertisements
    SupraForums.com
    Advertisements
     

  3. #2
    SupraForums Member
    Join Date
    Jun 2010
    Location
    Euless, TX
    Posts
    286
    i have similar problems when my a/c is on
    get some water wetter for your coolant its supposed to keep temps cooler
    do you still have the fan shroud on?
    '95 Diamond White Pearl SC300, 2jzgte swapped, APU

  4. #3
    SupraForums Member Esvilopez's Avatar
    Join Date
    Jun 2007
    Location
    Rhode Island
    Posts
    289
    Yes I do I just bought a bottle and see whath happens

  5. #4
    SupraForums Member
    Join Date
    Sep 2005
    Location
    canada
    Posts
    174
    It sounds like you don't have enough airflow. make sure the rad is not plugged, fans are coming on. See if it makes a difference with the ac on or off

  6. #5
    SupraForums Member
    Join Date
    Jun 2001
    Posts
    864

    Japanese Tuning in Plain English

    It's not your fan clutch... your symptoms would be the opposite. Hot when driving in town and cooler when on the highway.

    Water Wetter isn't your solution... it should run just fine without it.

    Lack of airflow would seem to be a suspect... although it runs really cool in town... overflowing coolant? I think it's something else.

    Your Radiator cap may be bad or it's not sealing properly on your new radiator. This in turn can allow an air pocket to develop... and usually right where the temp sensor is located.

    At higher speeds, when the flow is much greater, the pocket may become larger. IMO... that cheap ass Mishimoto radiator doesn't have the proper coolant flow capacity to keep up with the pump.

    I also think that the "Mishimoto Radiator Install Sticky" should be removed... why encourage crap? Seriously, WTF's a mishimoto anyways? It's not even a Japanese name...

    ... anyways... If you had to replace the radiator, chances are, the cap needs to be replaced as well.

    Choritsu-shi

  7. #6
    Raising the BAR Dj6ta's Avatar
    Join Date
    Sep 2010
    Location
    College Station, TX
    Age
    26
    Posts
    2,926
    Blog Entries
    2
    Quote Originally Posted by choritsu-shi View Post
    It's not your fan clutch... your symptoms would be the opposite. Hot when driving in town and cooler when on the highway.

    Water Wetter isn't your solution... it should run just fine without it.

    Lack of airflow would seem to be a suspect... although it runs really cool in town... overflowing coolant? I think it's something else.

    Your Radiator cap may be bad or it's not sealing properly on your new radiator. This in turn can allow an air pocket to develop... and usually right where the temp sensor is located.

    At higher speeds, when the flow is much greater, the pocket may become larger. IMO... that cheap ass Mishimoto radiator doesn't have the proper coolant flow capacity to keep up with the pump.

    I also think that the "Mishimoto Radiator Install Sticky" should be removed... why encourage crap? Seriously, WTF's a mishimoto anyways? It's not even a Japanese name...

    ... anyways... If you had to replace the radiator, chances are, the cap needs to be replaced as well.

    Choritsu-shi
    +1
    Downside to owning a Supra


    Quote Originally Posted by -defi- View Post
    down side? when girls get in and ask "where is the cup holder?"..... real question.... "Who the F*%! said you could bring a drink in here?!".

  8. #7
    SupraForums Member
    Join Date
    Jun 2010
    Location
    Euless, TX
    Posts
    286
    im running a koyo radiator with brand new koyo cap
    airflow is most definitely the problem hince the overheating
    if you are on the highway with ac on the ac is working harder which in turn will make the ac condensor run hotter
    i do believe the ac condensor is right in front of the radiator
    if you are like myself and have a 4" intercooler that aint gonna help either

  9. #8
    SupraForums Member
    Join Date
    Aug 2010
    Location
    Baytown Tx
    Age
    28
    Posts
    312
    make sure that if you are running a fmic that it's as close to the radiator as possible. when i had an sr in my 240 before i went 2j the fmic stuck too far forward and down too far which created the same scenario as you are decribing. the way i fixed it was by adding an air dam between the fmic and the radiator lower core support. it was an over glorified piece of aluminum sheet metal that was bolted to the bottom of the fmic and then screwed into the lower core support using self tapping screws. it was pretty much the same width as the fmic and flared out to the same width as the radiator. once i did that i had no more issues with overheating on the high way

  10. #9
    Raising the BAR Dj6ta's Avatar
    Join Date
    Sep 2010
    Location
    College Station, TX
    Age
    26
    Posts
    2,926
    Blog Entries
    2
    Logical analysis of your coolant system. Coolant flows through the radiator and block because the water pump is driven off the timing belt which goes faster when the RPM is higher. Thus, a reasonable car would heat up in a inverse ration to how much it is cooled by the faster moving water pump due to the high RPM. If a small blockage of pressure exist in the lines, pump or radiator then the inverse ratio of cooling would be interrupted causing line blows or over heating. Your cars radiator cap will release pressure into you overflow tank when proper pressure has been reached to avoid the above mentioned conditions. If a blockage exist before the cap then the car will continue to heat up more and more as the RPM goes up. If the car is at a lower RPM then the operating temp is lower, thus a small blockage won't cause overheating because the engine rpm is low enough to not build excess pressure. What im trying to say here is you either have a blockage of some sort and/or you need a new cap.

  11. #10
    SupraForums Member
    Join Date
    Aug 2010
    Location
    Baytown Tx
    Age
    28
    Posts
    312
    That's what everybody told me but it was simply an airflow issue of air being diverted away from the radiator by the fmic.

  12. #11
    SupraForums Member romir123's Avatar
    Join Date
    Jun 2009
    Location
    Miami Fl.
    Posts
    481
    My brother and I both have mishimoto radiators. No problems for over two years now. U say the radiator and thermostat are new. Why did u change them ?? Was it over heating before. Also brand of the thermostat . Also they have a way to be installed. They have a bleeder that is supposed to go at 12 o'clock
    ASE master tech L 1 advanced engine performance / Toyota master tech / Honda gold level tech


    Our supras, who art in the driveway, hallowed be thy name, thy speed has come, thy will never be done, on the road as it is on the mind, give us this day your daily beauty, and forgive us our speeding, as we forgive those who drive slow, and lead us not into incarceration, but deliver us from the five-o ....amen

    A beautiful Supra Prayer by: Kris Paczedlik

  13. #12
    SupraForums Member
    Join Date
    Jun 2010
    Location
    Euless, TX
    Posts
    286
    new radiator because i did an engine swap
    used oem thermostat that was in the car already
    i can drive all day long with no problems on the highway its ONLY WHEN AC IS ON not all the time

  14. #13
    Supra Owner
    Join Date
    May 2007
    Location
    New Orleans
    Posts
    529
    I had this problem with two supras. Both of them ended up being the koyo cap. The cap is a piece of crap. On both of them, i literally bought a cap from pepboys that fits. I never had the problem again on either supras.

    The koyo caps couldn't hold the pressure.



    Supras = PROVEN

  15. #14
    SupraForums Member
    Join Date
    Sep 2005
    Location
    canada
    Posts
    174
    make sure when your ac is on both fans are on. i assume you have 2 fans. if only one fan is on the extra load on the engine and the condenser temp getting higher will cause the engine to overheat on the hwy. if your only running one fan you will need a secondary fan that comes on with the ac. this should solve your problem

  16. #15
    SupraForums Member
    Join Date
    Aug 2010
    Location
    Baytown Tx
    Age
    28
    Posts
    312
    On highway u have more airflow than the fans can produce, hence why I said there is an aerodynamic problem between the front of the car and the radiator. If its not the radiator cap its airflow. If it was a blockage it would show issues in town as well.

  17. #16
    SupraForums Member
    Join Date
    Sep 2005
    Location
    canada
    Posts
    174
    I work at a dealer and i see it all the time usually one of the fans is bad and it overheats on the hwy. and these are just stock vehicles.

  18. #17
    SupraForums Member romir123's Avatar
    Join Date
    Jun 2009
    Location
    Miami Fl.
    Posts
    481
    Quote Originally Posted by mudpy View Post
    I work at a dealer and i see it all the time usually one of the fans is bad and it overheats on the hwy. and these are just stock vehicles.
    Wtf lol. Why would it overheat on the highway with a bad fan ??

  19. #18
    SupraForums Member
    Join Date
    Jun 2010
    Location
    Euless, TX
    Posts
    286
    both mine work
    so thats not the case
    def an airflow issue

  20. #19
    SupraForums Member
    Join Date
    Aug 2010
    Location
    Baytown Tx
    Age
    28
    Posts
    312
    That's what I keep saying....

    1989 2j40sx Coupe
    2002 Explorer 5 spd

  21. #20
    SupraForums Member mhooper2's Avatar
    Join Date
    Oct 2006
    Location
    New Smyrna, FL
    Age
    31
    Posts
    1,510
    Quote Originally Posted by kuzi View Post
    both mine work
    so thats not the case
    def an airflow issue
    Post pictures of your setup.
    Facebook: https://www.facebook.com/SupraHooper?ref=tn_tnmn
    Supra and 2JZ Dscussion- https://www.facebook.com/groups/138064263050351/
    New parts a the best prices-https://www.facebook.com/APlusSPS
    I also BUY parts for CASH at a discounted rate for those that don't want to deal with selling them or are in a PINCH!

  22. #21
    Supra Owner
    Join Date
    May 2007
    Location
    New Orleans
    Posts
    529
    i doubt it, if it was an airflow issue, it should over heat in both hwy and street use. on the hwy u get way more airflow then the fans alone sitting in traffic. If you cant get the airflow on the hwy, what makes u think the fans can pull enough air when sitting still. If you cant get enough air through the the front when there is massive pressure coming in when driving, how in the hell can the fans pull enough air when no air is being pushed through.

  23. #22
    Raising the BAR Dj6ta's Avatar
    Join Date
    Sep 2010
    Location
    College Station, TX
    Age
    26
    Posts
    2,926
    Blog Entries
    2
    Quote Originally Posted by rory View Post
    i doubt it, if it was an airflow issue, it should over heat in both hwy and street use. On the hwy u get way more airflow then the fans alone sitting in traffic. If you cant get the airflow on the hwy, what makes u think the fans can pull enough air when sitting still. If you cant get enough air through the the front when there is massive pressure coming in when driving, how in the hell can the fans pull enough air when no air is being pushed through.
    x2

  24. #23
    SupraForums Member
    Join Date
    Feb 2001
    Location
    SE PA
    Age
    65
    Posts
    12,560
    ^ exactly. Fans are for cooling when you are stopped or barely moving. Once you get going it's all airflow and fans just potentially get in the way.
    Nick 95 6sp
    Twin Garrett GT2860's w/TiAL exhaust housings, WG's and BOV's, on V-band moded HKS twin manifolds, AEM v2, AEM WB, ID1000's,
    AEM meth/water spray kit, GSC S1 cams, ported head Ferrea valvetrain, +0.020" CP pistons w/crown & skirt coatings, Carrillo H-beams,
    OS Giken triple clutch & Super Lock LSD, Racelogic TC, TRD gen2 catback
    street wheels: Veilside EvoV 9-1/2"F X 10-1/2"R with 265/35F & 285/35R NT05's
    track wheels: CCW LM5 10"F X 11-1/2"R with 285/30F & 315/30R R888's

  25. #24
    SupraForums Member
    Join Date
    Aug 2010
    Location
    Baytown Tx
    Age
    28
    Posts
    312
    Quote Originally Posted by Rory View Post
    i doubt it, if it was an airflow issue, it should over heat in both hwy and street use. on the hwy u get way more airflow then the fans alone sitting in traffic. If you cant get the airflow on the hwy, what makes u think the fans can pull enough air when sitting still. If you cant get enough air through the the front when there is massive pressure coming in when driving, how in the hell can the fans pull enough air when no air is being pushed through.

    Something causing a diversion like a fmic too far out. In town the fans can pull enuff air to cool properly but the fmic being out too far can actually create a vortex or vacuum between the fmic and radiator.

    I know this from personal experience

  26. #25
    SupraForums Member
    Join Date
    Jun 2010
    Location
    Euless, TX
    Posts
    286
    i want to say i have about 3-3.5inches in between my 4" fmic and my ac condensor

+ Reply to Thread
Page 1 of 2 1 2 LastLast

Similar Threads

  1. Drag Radial for city/highway runs/occasional 1/4 mile runs
    By JoeSupra in forum Shops & Part Reviews
    Replies: 28
    Last Post: 08-16-2010, 04:04 PM
  2. Overheating on highway...
    By CSquared in forum MKIII Technical
    Replies: 5
    Last Post: 03-26-2005, 09:26 PM
  3. Highway A/F
    By mikkee123 in forum MKIII (1986.5-1992)
    Replies: 3
    Last Post: 06-11-2004, 02:01 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts