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LS cooling question


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I'm running the stock 240Z radiator with an electric fan. Since I dont have a heater I simply have the heater lines looped together through a reducer fitting. It is not orificed rather is just a straight adapter. My LS1 runs cool at idle (with fan on), runs cool going down the road, but I notice when I race that the coolant temp rises after each run and progressively gets hotter each run. Since so far I've only had the stock gauge I just know it goes from the normal first leg of the M in the TEMP on the gauge face up into the bottom or middle of the P. I've just installed but yet to run a full sweep electric Autometer so next season I will know in degrees where I am at. I've only run a few laps at a time on open track + many autox so no 20 minute sessions or anything that would really get things hot. I'm wanting pro actively improve my cooling before I hit any more extended track days. I've already sealed off the front end and ducted to the radiator plus vented out the drivers side inspection lid.

 

So now where do I go? Since 95% of my driving with the current set-up has proven to be fine I dont want to spend a lot of $ fixing something that isn't too broken but at the same time I dont want to get into trouble at a track day this Summer. At first I was thinking of getting a nice aluminum radiator but being cheap was wondering what else I could try first. I also wonder if the temp ratchets up because the oil is progressively getting hotter. I'm wondering if I'm losing a lot of cooling through the looped heater line. My old L motor had the line looped like this but am wondering with the LS if it matters one way or another or any other ideas I may be missing. If it's the oil that's the source of the heat maybe an oil cooler would be money better spend?

 

Thanks

Cameron

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cam, couple thoughts from my experience with the ls swap. i'm using a 160 tstat. will be putting the 180 back shortly. 2nd, it may [the gauge] be sampling the temp from either the warmer or cooler head. the heads are not directly connected for coolant. i discovered this as my gauge read one temp and the laptop [while tuning] was reading about 20 different. remedied by tapping the back 2 coolant fittings and tying them together.

 

also, keep in mind that gm designed this engine to run around 200-210, with our L6's are not used to temp that high. perhaps yours is just getting up to the proper temp.

 

not sure how much this will help but hope it will...

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What is your peak temp you get to when you see it rising? I have the same "looped" setup on my Z but I am running a big rad and the GM dual E fans. I still have the 180 tstat in my car. Driving around and short speed burst I am around 190 but on track (Watkins Glen or Daytona yr ago) my temp got up to 205-210 exactly where you want to be. Like David said, GM designed the LSx's to run warmer than our L6....the exact reason I did not do the 160 tstat. Also...as I will be doing this season....get rid of that Dextron coolant....it is junk!

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2nd, it may [the gauge] be sampling the temp from either the warmer or cooler head. the heads are not directly connected for coolant. i discovered this as my gauge read one temp and the laptop [while tuning] was reading about 20 different. remedied by tapping the back 2 coolant fittings and tying them together.

 

That's interesting as I just installed the sender in the passenger side head where I've been using the block plug on the drivers side. Hmmm - wonder how this will work out. I wish I knew what I've been running other than in as high as the 'P' on the stock gauge. The stock gauge doesn't really have degrees just the word TEMP written across it. I'm going to wait and see what the new gauge says but now I'm worried about the location - errr.

 

Cameron

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  • 2 weeks later...

If I remember correctly the 240Z has a 2-row radiator. Is yours original? The 280Z has a 3-row radiator. My LS1 conversion uses a 280Z radiator recored to a 4-row with the fans & shroud from the Z28 donor car. Never have a bit of overheating problem under any conditions. If you are marginal you might shop a use 280Z radiator. It will significantly improve your cooling over the 2-row 240Z unit.

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  • 2 months later...

My engine guy said using a oil cooler will help out alot, My 355 has a bds blower onit and it runs really hot I am using the stock 300zx radiator and two 11ich electric fans. That is not enough. I was using two temp gauges (autometer) one in the intake by the distributor and one in the drivers head. The one in the intake that ive heard runs 20 to 30 degrees cooler then the one in the head which makes sense. Haven one in the head is the best bet, but also ive heard using "water weter" i think thats wat it is called helps mix that in with ur coolant. Ive also heard looping ur heater hoses together doesnt really help just plug them off in the intake. ONes pluged on mine and one has the temp gauge in it. I also use a csr electric water pump due to the blower.

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Mine are plugged too. At first I thought I wasn't cooling enough because the temp would creep up when on it hard. But, it never goes above 210. I even thought my fans were not working because they never came on (Stock Camaro Fans). I have an aluminum radiator and it was doing such a good job at cooling, I never reached normal operating temp and so the fans wouldn't come on. I have since learned that they do. I just have to drive hard long enough.

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