Overheats only when driving at high speeds
Overheats only when driving at high speeds
Good afternoon everyone. i did the na/tt swap and it went fine. fixed everything that was needed for it to be driven but i didnt have ac since the pipings wouldnt let the condenser fit. i went without ac for about 4 months before i couldnt stand it anymore. i got a custom ac condenser made. now the car overheats at high speeds mainly on the highway. i have 3 electric fans connected and just removed my thermostat, i lost my performance thermostat -_- and it still gets hot. but when im on idle or get off the highway, it gets back to normal. any suggestions? i have a 68 mustang radiator . only one that would fit it and it was working perfect till the ac was made. and ive also seen radiator fluid on weird places, like under my hood dripping from it or other random places. i believe thats caused by being overheated, it gets too hot and the pressure sprayed the fluid from places, but i cant find from where.
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NizzyTheZ&Me
- Posts: 6
- Joined: Sat Dec 28, 2013 12:46 pm
- Car: 90 300zxtt
Re: Overheats only when driving at high speeds
Went thru a similar issue just last week. Was overheating on highway coming back from FL to TN. The problem ended up being airflow to the radiator. Try taking the nose piece off the front. Leads air right to radiator (wish I had thought of this on mine before paying for what was told was bad water pump). If it runs cooler, check to see if you still have the plastic undersheets (not sure tech description) mine had it missing and air was going under radiator not thru it. Ended up making something out of sheet aluminum and has worked wonders on my hwy temps, now just need appropriate efan for city driving too replace the crappy undersized one PR had on it.
Don't have pics right now, and bit sure how to post them. But can if you want to see what I mean.
Don't have pics right now, and bit sure how to post them. But can if you want to see what I mean.
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AZhitman
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- Car: 58 L210, 63 Bluebird RHD, 64 NL320, 65 SPL310, 66 411 RHD, 67 WRL411, 68 510 SR20, 75 280Z RB25, 77 620 SR20, 79 B310, 90 Z32, 91 GTi-R, 92 Silvia Qs, 98 S14, 23 Z.
- Location: Surprise, Arizona
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Re: Overheats only when driving at high speeds
This one might make ya feel dumb, but double check the rotation of the e-fans. If they are pushing air OUT through the radiator (against the direction of travel), it'll stay cool when stopped or at low speeds, then overheat when at speed (basically, creating a "dead air" space within the radiator fins).
Easy to test, just feel behind them at idle and see if the air blows INTO the engine bay or out. Drop some talcum powder in front of the bumper opening to check - if it gets sucked into the radiator, you have other issues - if it blows out, I win a cookie.
If they're reversed, just reverse the polarity on the fan wiring.
Easy to test, just feel behind them at idle and see if the air blows INTO the engine bay or out. Drop some talcum powder in front of the bumper opening to check - if it gets sucked into the radiator, you have other issues - if it blows out, I win a cookie.
If they're reversed, just reverse the polarity on the fan wiring.
Re: Overheats only when driving at high speeds
I have 3 electric fans blowing the same direction. All towards the engine. And I dnt think there's enough air getting to the engine at high speeds because theses a condenser between radiator and front bumper. And Nizzy, a picture would help. Do you mean taking off the front bumper?
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NizzyTheZ&Me
- Posts: 6
- Joined: Sat Dec 28, 2013 12:46 pm
- Car: 90 300zxtt
Re: Overheats only when driving at high speeds
Not the front bumper just the piece between the headlights. I tried it when got home from vacation, and worked great to let me know the problem was airflow. There is a lot in front of the radiator, but it made a straight path to it that let cooler air get to the radiator, even if thru the condenser.
I'm stuck using my phone for internet right now, but I'll see what I can do for pics.
I'm stuck using my phone for internet right now, but I'll see what I can do for pics.
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AZhitman
- Administrator
- Posts: 54540
- Joined: Mon Apr 29, 2002 2:04 am
- Car: 58 L210, 63 Bluebird RHD, 64 NL320, 65 SPL310, 66 411 RHD, 67 WRL411, 68 510 SR20, 75 280Z RB25, 77 620 SR20, 79 B310, 90 Z32, 91 GTi-R, 92 Silvia Qs, 98 S14, 23 Z.
- Location: Surprise, Arizona
- Contact:
Re: Overheats only when driving at high speeds
Why a '68 Mustang radiator? How many cores? If it's not thick enough or doesn't have enough fins, there will be insufficient surface area to extract heat from the coolant - the air passes through it way too fast. I'm thinking that's a big issue right there.
Cars didn't require a lot of cooling back then - a simple single-core radiator was sufficient. Not sure why you'd put Flintstones technology in a modern Z.
Cars didn't require a lot of cooling back then - a simple single-core radiator was sufficient. Not sure why you'd put Flintstones technology in a modern Z.
Re: Overheats only when driving at high speeds
The mustang radiator has 3 rows 16 x 16. And it was cooling effectively before I installed an ac condenser. I went 3 months without ac and never had a problem with overheating.
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AZhitman
- Administrator
- Posts: 54540
- Joined: Mon Apr 29, 2002 2:04 am
- Car: 58 L210, 63 Bluebird RHD, 64 NL320, 65 SPL310, 66 411 RHD, 67 WRL411, 68 510 SR20, 75 280Z RB25, 77 620 SR20, 79 B310, 90 Z32, 91 GTi-R, 92 Silvia Qs, 98 S14, 23 Z.
- Location: Surprise, Arizona
- Contact:
Re: Overheats only when driving at high speeds
Hmm. I'd still be concerned about fin density.
Remember, the condenser sheds a lot of heat - so, whatever happened before adding AC won't have any real bearing on the situation now.
However, the next area (unless you have the tools to measure pressure drop and airflow) should be to look at the path of airflow. Pics here would help a ton. I've done a lot of work on custom applications that require airflow management (hypermilers and high-hp builds with minimal front surface area), so pics of your current setup would help a ton.
I'm wondering if a v-mount setup might not help your issues. On our '72 Z with an RB swap, we have the radiator and intercooler slightly v-mounted to make better use of space.
Remember, the condenser sheds a lot of heat - so, whatever happened before adding AC won't have any real bearing on the situation now.
However, the next area (unless you have the tools to measure pressure drop and airflow) should be to look at the path of airflow. Pics here would help a ton. I've done a lot of work on custom applications that require airflow management (hypermilers and high-hp builds with minimal front surface area), so pics of your current setup would help a ton.
I'm wondering if a v-mount setup might not help your issues. On our '72 Z with an RB swap, we have the radiator and intercooler slightly v-mounted to make better use of space.