car is still overheating, think it might be water pump?

Discuss the RB20, RB25 and RB26 series engines.
Sky240PWR
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Joined: Sun Feb 27, 2005 9:27 pm
Car: 1991 Nissan 240SX

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Well my car has be overheating for awile now, I've checked my radiator for leaks, and checked my oil but both are fine. When i drive i keep my heater on high and that helps keep it down some. My mechanic can't get to my car untill the 9th and it's had this problem for two or three weeks now!! someone told me it might be the water pump, when it overheats it doesn't drive any differnt or smoke or anything. I just wanted to hear what you guys think. and if you do think it's the pump, where can i get one pretty cheap and within a couple weeks?


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StricNyne
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Joined: Thu Oct 30, 2003 1:11 pm

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check lower radiator sensor, btw do u machine rb26 rods ?

Imissmyturbo
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Joined: Fri Jan 03, 2003 1:55 pm
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What do you have for a radiator....Also what intercooler do you have? I would check to make sure you are getting good airflow to your radiator.

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Eikon
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Water pump was the culprit for me. I checked for Head Gasket, Radiator, heater core, flushed the system, purged for air bubbles, etc... nothing worked. I thought that it couldn't be the water pump because it wasn't leaking or anything...

Turns out the water pump was completely shot inside. All the impeller fins were totally corroded away.

see my thread... zerothread?id=97865

My car drove the same either way. My symptoms were pretty unique.. if you share these symptoms you should guess it's the water pump.

1.) heater worked funny... Turn your heat on as high as you can. The heater core requires a water pump to force fluid in motion through the system. When you car is running hot, when you first turn your heater on to full heat, you will get hot air, but it will gradually cool down and eventually you will get almost not heat. If the water pump is not moving the system, no fluid will get into the heater core, and you will get heat from what's in there, but as you use the heat, it will not cylce more hot fluid in there.

2.) The car overheated only when driven on the highway for extended times, or when boosting. Granted my driving at that time was when it was very cold outside... but, the car didn't seem to have a problem just making short trips in town. But when it ran continuously on the highway it overheated... of course I didn't let it.. I would always pull over to the side of the road.

3.) No other explanation.... like I said.. we pretty much eliminated everything else.. test for bad head gasket, try flushing the coolant system to make sure you don't have some sort of build-up. purge the coolant system so you don't have any bubbles. Try pressure testing the coolant system to see if there's a leak or something somewhere. If none of those things help... it's your water pump.

The only other thing I could think of is perhaps the sensor is bad. But, you should know from popping the hood if the car is really hot.

Get a heat laser. My mechanic said their like $20. Shoot it at the coolant pipe and see what readings you get.

Good luck!!!

oh.. where to get one.. First.. try our sponsors. Call them and ask if they can get you one quickly. If no luck with sponsors, phase2motortrend has them... $129. Email JonPowell... somebody he does business with has them if I remember. RBmotoring?There around... you'll find one.

later


Imissmyturbo
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I was able to check my water pump out by taking the Thermostate out. you can see the blades if you do that.

Yellow4g63
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Joined: Mon Jan 20, 2003 6:07 pm
Car: 95 Nissan RB20 240SX RB20
91 Nissan NX2000 VE power
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My car use to overheat too. 1st I bought some good fans, then it helped a little bit. Then I bought a bigger/new radiatior and it's all gude now.

Cornloaf
Posts: 258
Joined: Sun Jan 23, 2005 10:23 am
Car: 1990 240sx

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a brand new N1 waterpump just sold on ebay for under $150 shipped.

Sky240PWR
Posts: 1248
Joined: Sun Feb 27, 2005 9:27 pm
Car: 1991 Nissan 240SX

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well i have a Koyo radiator and a greddy intercooler, and i have a pretty big fan but it's not the FAL twin one!
Cornloaf wrote:a brand new N1 waterpump just sold on ebay for under $150 shipped.
thats a pretty good price but i've never bought anything off ebay.(trust) was it for a RB25? cause thats what i have!

and as far as a leak, i know there isn't one cause i checked and the coolant level is still where it was last time i checked.

frosted flakes
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Joined: Tue May 13, 2003 9:02 am
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check your temp sensor that goes the gauge cluster.

you MUST use the temp sensor that goes with your gauge cluster. i thought my car was overheating cuz it was always in the H but it never boiled over so i thought something was iffy. so i put in the s14 temp sensor and my gauge read normal.

ha i thought it was overheating but really my gauge just wasnt reading right.

Sky240PWR
Posts: 1248
Joined: Sun Feb 27, 2005 9:27 pm
Car: 1991 Nissan 240SX

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frosted flakes wrote:check your temp sensor that goes the gauge cluster.

you MUST use the temp sensor that goes with your gauge cluster. i thought my car was overheating cuz it was always in the H but it never boiled over so i thought something was iffy. so i put in the s14 temp sensor and my gauge read normal.

ha i thought it was overheating but really my gauge just wasnt reading right.
well i have a water gauge temp and thats what i'm going on.

Ramius83
Posts: 740
Joined: Sat Apr 19, 2003 8:58 am
Car: 1995 240sx SE
Location: Cumming, GA

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What is the brand of your water temp gauge? Is it new or used? Age if used? They are generally very cheap. I would try maybe getting another one before you go into the water pump replacing route for something that may not be wrong.

Sky240PWR
Posts: 1248
Joined: Sun Feb 27, 2005 9:27 pm
Car: 1991 Nissan 240SX

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well if i remember right there Tenzo R, and they are only 4 months old. Mickinney put them in when they put my motor in!

I know it's overheating cause i smell the coolant after a while.It goes in the shop on the 9th.


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