Results 1 to 22 of 22

Thread: Z is Overheating

  1. #1
    Registered User ohio260z's Avatar
    Member ID
    CZCC-16458
    Join Date
    Mar 2008
    Location
    Lexington, Ohio, United States
    Age
    32
    Posts
    30

    Default Z is Overheating

    I dont know what is causing the Z to overheat. The radiator is brand new and it has a new thermostat. It is a late 74 260z all stock. any help would be great.
    -Josh

    74 260z

  2. #2
    Registered User d240zx2's Avatar
    Member ID
    CZCC-15137
    Join Date
    Sep 2007
    Location
    Houston, Texas
    Age
    76
    Posts
    1,334

    Default

    Did you "burp" it?

    Frank
    First & Third owner of HLS30-00721
    B. 01/70 D. 03/12

    New owner of HLS30-15653
    B. 12/70 D.

    Frank in Houston, Texas

  3. #3
    Registered User ohio260z's Avatar
    Member ID
    CZCC-16458
    Join Date
    Mar 2008
    Location
    Lexington, Ohio, United States
    Age
    32
    Posts
    30

    Default

    Quote Originally Posted by d240zx2 View Post
    Did you "burp" it?

    Frank
    What do you mean by that?
    -Josh

    74 260z

  4. #4
    Registered User 240ZX's Avatar
    Member ID
    CZCC-1420
    Join Date
    Dec 2001
    Location
    Santa Paula, California
    Age
    69
    Posts
    1,884

    Default

    Was the engine flushed?

    Tom

  5. #5
    Registered User d240zx2's Avatar
    Member ID
    CZCC-15137
    Join Date
    Sep 2007
    Location
    Houston, Texas
    Age
    76
    Posts
    1,334

    Default Burping...

    Sometimes, when filling a drained cooling system, an air pocket is formed at the highest point in the cooling system, which is the t-stat housing. You've got to clear that air pocket in order for the coolant to flow and cool properly, thus the term "burp."

    Some folks choose to heartily squeeze the upper radiator hose to create a bit of slosh that works the bubble out after a few squeezes. Others choose to release the hose clamp at the t-stat housing, pull the hose back just enough to let the air escape, reposition, and tighten the clamp. I like the second method as you are sure the pocket is gone.

    Hope this helps!

    Frank
    First & Third owner of HLS30-00721
    B. 01/70 D. 03/12

    New owner of HLS30-15653
    B. 12/70 D.

    Frank in Houston, Texas

  6. #6
    No more body roll! SteveJ's Avatar
    Member ID
    CZCC-5413
    Join Date
    Dec 2003
    Location
    Gainesville, GA
    Age
    54
    Posts
    3,651

    Default

    What is the condition of the water pump & the belt that turns it?
    73 240Z
    74 260Z

    Blue's collection of tech tips - A great place to look for answers
    XenonS30 -The cheap source for FSMs
    Georgia Z Club
    Fiddling with Z Cars - Z car tips & tricks and pictures of my car-loving life.
    Steve's CARtography - Just car pictures.

  7. #7
    Registered User bobc's Avatar
    Member ID
    CZCC-9737
    Join Date
    Oct 2005
    Location
    Orange, California
    Posts
    344

    Default

    I think we could help you more if you provided a little more info:

    1. Why was the radiator replaced?
    2. Was it overheating before the radiator was replaced?
    3. Have you checked the timing?
    4. Have you checked the idle mixture?
    5. When does it overheat? At idle? Under heavy load? Just cruising?
    6. Condition of lower radiator hose? Does it collapse under load?

    Since you replaced the radiator and thermostat it sounds like maybe you were having this problem prior to the work? If so:

    7. Has it been using any water? That is have you had to add water to the radiator often to keep it filled?

    I think if you answer these it will help us point you in a more specific direction.

    Good luck

    Best,

    Bob

  8. #8
    Registered User ohio260z's Avatar
    Member ID
    CZCC-16458
    Join Date
    Mar 2008
    Location
    Lexington, Ohio, United States
    Age
    32
    Posts
    30

    Default

    Quote Originally Posted by SteveJ View Post
    What is the condition of the water pump & the belt that turns it?
    the water pump is new back in the spring the belt is decent but probably needs replaced next year.
    -Josh

    74 260z

  9. #9
    Registered User ohio260z's Avatar
    Member ID
    CZCC-16458
    Join Date
    Mar 2008
    Location
    Lexington, Ohio, United States
    Age
    32
    Posts
    30

    Default

    Quote Originally Posted by bobc View Post
    I think we could help you more if you provided a little more info:

    1. Why was the radiator replaced?
    2. Was it overheating before the radiator was replaced?
    3. Have you checked the timing?
    4. Have you checked the idle mixture?
    5. When does it overheat? At idle? Under heavy load? Just cruising?
    6. Condition of lower radiator hose? Does it collapse under load?

    Since you replaced the radiator and thermostat it sounds like maybe you were having this problem prior to the work? If so:

    7. Has it been using any water? That is have you had to add water to the radiator often to keep it filled?

    I think if you answer these it will help us point you in a more specific direction.

    Good luck

    Best,

    Bob
    1 radiator was replaced because the water pump shaft broke causing the fan to go into the radiator.
    2 it wasn't over heating before the radiator was replaced
    3 timing has not been checked since i have had it (4 years)
    4 idle mixture has not been check
    5 it started to overheat today and i was just cruising it was about 84 today
    6 lower radiator hose doesn't collapse under load and is in good condition
    7 yes it is using water i have had to refill it a couple of times lately
    replaced the thermostat because it was overheating

    Thank You for all the help

    Josh
    -Josh

    74 260z

  10. #10
    Supporting Member EScanlon's Avatar
    Member ID
    CZCC-1490
    Join Date
    Dec 2001
    Location
    Vancouver, WA
    Age
    64
    Posts
    4,874

    Default

    Having to refill the radiator "a couple of times" says you have a serious leak. Check the engine front, hoses and block for signs of where it's coming out.

    The thermostat may not necessarily be the reason for the overheating. I've been told that sometimes NOT having one can cause the engine to over heat due to not allowing the coolant to remain in the radiator long enough to shed heat.

    FWIW
    E

  11. #11
    Former frequent poster sblake01's Avatar
    Member ID
    CZCC-3797
    Join Date
    Mar 2003
    Location
    San Bernardino, Ca. U.S.A.
    Age
    70
    Posts
    10,574

    Default

    Quote Originally Posted by ohio260z View Post
    ..........7 yes it is using water i have had to refill it a couple of times lately
    replaced the thermostat because it was overheating..........
    Using water? If you don't see it leaking then you've got an internal problem. I once had a water pump shaft break on a 79 510 and it caused a small hole in the timing cover that allowed just enough coolant to seep into the engine and cause it to overheat but not enough to be really noticeable until it got worse. At that point, I thought I'd blown a head gasket until I removed the water pump and saw the damage behind it on the timing cover.
    2004 Ford Ranger EDGE Supercab
    (@Moonpup: This one really is an EDGE!)
    2005 Pontaic GTO
    2010 Mercedes Benz C300 AMG Sportline (Wife's car)
    2014 Kia Rio LX (Wife's daily driver)
    Certified HVAC/MVAC Technician

  12. #12
    Registered User ohio260z's Avatar
    Member ID
    CZCC-16458
    Join Date
    Mar 2008
    Location
    Lexington, Ohio, United States
    Age
    32
    Posts
    30

    Default

    Quote Originally Posted by sblake01 View Post
    Using water? If you don't see it leaking then you've got an internal problem. I once had a water pump shaft break on a 79 510 and it caused a small hole in the timing cover that allowed just enough coolant to seep into the engine and cause it to overheat but not enough to be really noticeable until it got worse. At that point, I thought I'd blown a head gasket until I removed the water pump and saw the damage behind it on the timing cover.
    Im not sure if this has to due with the cooling system but since you said it may be internal there is some type of fluid that is coming out of the little k&n filter on the valve cover. i think it is a mixture of water and oil but im not sure. the head gasket does not seem to be blown but i dont know all the ways to check, i did check the oil and it is not milky at all.

    Josh
    -Josh

    74 260z

  13. #13
    HS130-150591 4/79 zbane's Avatar
    Member ID
    CZCC-11908
    Join Date
    Jun 2006
    Location
    Cashiers, NC
    Age
    48
    Posts
    1,671

    Default

    Quote Originally Posted by ohio260z View Post
    . the head gasket does not seem to be blown but i dont know all the ways to check, i did check the oil and it is not milky at all.
    When my head gasket blew, none of the coolant made its way to the crankcase (or at least not enough to be visible). I had been overheating, and had replaced everything you have, including the radiator at 1 in the morning, in the rain.
    Have you checked your compression? That was the final indicator in my case, as well as the car simply refusing to start...
    David
    _____________________________________
    HS130-150591, April, 1979-280zx
    2001 Infiniti I 30

  14. #14
    Registered User ohio260z's Avatar
    Member ID
    CZCC-16458
    Join Date
    Mar 2008
    Location
    Lexington, Ohio, United States
    Age
    32
    Posts
    30

    Default

    Quote Originally Posted by zbane View Post
    When my head gasket blew, none of the coolant made its way to the crankcase (or at least not enough to be visible). I had been overheating, and had replaced everything you have, including the radiator at 1 in the morning, in the rain.
    Have you checked your compression? That was the final indicator in my case, as well as the car simply refusing to start...
    the car still runs pretty strong but i would guess that doesn't mean that one cylinder has a leak in it. i also discovered that there might be some kind of blockage in the coolant system due to the fact that the coolant doesn't seem to be flowing and then the thermostat opened up causing coolant to overflow out of the top of the radiator.
    -Josh

    74 260z

  15. #15
    HS130-150591 4/79 zbane's Avatar
    Member ID
    CZCC-11908
    Join Date
    Jun 2006
    Location
    Cashiers, NC
    Age
    48
    Posts
    1,671

    Default

    Since you have discovered an apparent blockage, I might suggest a complete drain (make sure the heater controls are set to hot so that the coolant in there can drain as well). How you do this is up to you, but I purchased a Prestone back flush kit and fit the "T" connector on the right hand side of the block behind the "J" tube between spark plugs 1 and 2. Fairly simple operation, cut out some of the old tubing, install, tighten, and follow directions.
    Others may have other ways to do it, but I like the kit since it allows you to top off the radiator from below the upper edge, helping force the air bubbles out.
    David
    _____________________________________
    HS130-150591, April, 1979-280zx
    2001 Infiniti I 30

  16. #16
    HS130-150591 4/79 zbane's Avatar
    Member ID
    CZCC-11908
    Join Date
    Jun 2006
    Location
    Cashiers, NC
    Age
    48
    Posts
    1,671

    Default

    A photo should explain it a bit better.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	prestoneT.jpg 
Views:	101 
Size:	604.4 KB 
ID:	24440  
    David
    _____________________________________
    HS130-150591, April, 1979-280zx
    2001 Infiniti I 30

  17. #17
    Registered User ohio260z's Avatar
    Member ID
    CZCC-16458
    Join Date
    Mar 2008
    Location
    Lexington, Ohio, United States
    Age
    32
    Posts
    30

    Default

    the only thing that makes it a little weird that i flushed the system back in the spring and i have been driving it since may a couple times a week so it could be a good possibility that the head gasket is blown or i have an internal leak due to the fluid that is coming out of the little k&n filter on the valve cover
    -Josh

    74 260z

  18. #18
    beandip beandip's Avatar
    Member ID
    CZCC-1887
    Join Date
    Mar 2002
    Location
    Beaverton, Oregon
    Age
    81
    Posts
    4,038

    Default

    If you have water in the oil , get it out of there ASAP and flush the engine with good oil and a new filter. Water in the oil , the oil turns into mayonnaise and is a poor lubricant . Plus if there is oil in the water it will raise hell with the new rad.
    I'd rather die while I am living than live while I am dieing. CZC 1887 IZCC 12602 Member of NorthWest Z Car Club

  19. #19
    Registered User ohio260z's Avatar
    Member ID
    CZCC-16458
    Join Date
    Mar 2008
    Location
    Lexington, Ohio, United States
    Age
    32
    Posts
    30

    Default

    Quote Originally Posted by beandip View Post
    If you have water in the oil , get it out of there ASAP and flush the engine with good oil and a new filter. Water in the oil , the oil turns into mayonnaise and is a poor lubricant . Plus if there is oil in the water it will raise hell with the new rad.
    is there a way to tell if there is oil in the water i have never dealt with a problem like this before if it means i need to do a rebuild then thats what i will do just gives me a reason to start a refresh on the car
    -Josh

    74 260z

  20. #20
    Registered User Tarmac's Avatar
    Member ID
    CZCC-16976
    Join Date
    May 2008
    Location
    Tucson, AZ
    Age
    54
    Posts
    115

    Default

    Drain the oil. If it's milky, it's got water in it. Looking at the dipstick wont really tell you if it's got water in it unless it has a LOT.

  21. #21
    Registered User ph240's Avatar
    Member ID
    CZCC-13492
    Join Date
    Dec 2006
    Location
    Winston Salem NC
    Posts
    59

    Default

    If the old water pump broke it could have worn a hole in the timing cover which would explain the "Milky oil" in the crank case filter. As the bearings wear the shaft cam move causing the impellers to cut into the timing cover. You can pressurize the cooling system to about 15 to 20 lbs with a cooling system pressure tester and see if it will hold pressure, if not remove the valve cover, look down at the timing chain where the water pump would be. It sounds like a timing cover or blown head gasket.
    This does require your attention as it will lead to more seriuos problems.

  22. #22
    Registered User ohio260z's Avatar
    Member ID
    CZCC-16458
    Join Date
    Mar 2008
    Location
    Lexington, Ohio, United States
    Age
    32
    Posts
    30

    Default

    Quote Originally Posted by ph240 View Post
    If the old water pump broke it could have worn a hole in the timing cover which would explain the "Milky oil" in the crank case filter. As the bearings wear the shaft cam move causing the impellers to cut into the timing cover. You can pressurize the cooling system to about 15 to 20 lbs with a cooling system pressure tester and see if it will hold pressure, if not remove the valve cover, look down at the timing chain where the water pump would be. It sounds like a timing cover or blown head gasket.
    This does require your attention as it will lead to more seriuos problems.
    Thank you everyone for your help! This problem will more than likely not get fixed until this winter because it is not worth fixing when i want to pull the engine and do a rebuild on it. And the transmission needs some work along with a few other things that need some attention. Also the car will not be driven due to the fact of causing more damage.
    -Josh

    74 260z

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. overheating problem why???
    By 280zgod in forum Help Me !!
    Replies: 13
    Last Post: 01-26-2005, 01:29 PM
  2. Still overheating
    By 78 280zcar in forum Engine and Drivetrain (S30)
    Replies: 14
    Last Post: 12-15-2003, 12:23 AM
  3. Zcar overheating help
    By 78 280zcar in forum Engine and Drivetrain (S30)
    Replies: 6
    Last Post: 12-07-2003, 09:11 PM
  4. Overheating issues?
    By blitzkraig in forum Engine and Drivetrain (S30)
    Replies: 8
    Last Post: 09-11-2003, 01:01 PM

Bookmarks

Bookmarks

Posting Permissions

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