sr20det redtop overheating, cools under acceleration - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

moose4130 · 12-07-2016, 06:01 PM

I have searched, and tried what I have found. I purchased an s14 with sr20det swap already done. I discovered that it has an overheating issue, the temp spikes after 10-15 minute drive. The car has some heat, not super hot. In looking into this, I have replaced the thermostat, tried a different rad cap, topped off the overflow tank, and have had to replace the outlet pipe, because the bleeder screw was broken off in the old one. Since then, I have jacked the front end as high as I can and filled the system with a spill free funnel. I filled it with the car running and heater on, and after it was up to normal temp, I took the bleeder screw out for a second, coolant surged out, and I replaced the screw. I let the car run for a while with the heater on, and the gauge was roughly halfway up. I took the car for a quick spin to see if it helped, and it got hot, to the top of the normal range of the gauge. Upon returning, I discovered the gauge drops dramatically under acceleration.

Any advice? The radiator is an aluminum radiator with electric fans that have a good shroud and dual fans.

jr_ss · 12-07-2016, 08:21 PM

Do you have the correct temp sensor for the gauge cluster? S13 and S14 use different sensors for the gauge.

Next would be modifications done to the car/motor specifically. A full list. Do you have a wideband? If so, what is it reading at idle?

moose4130 · 12-08-2016, 06:20 AM

Unfortunately I don't have a wideband, but the narrowband is pegged at 2.5 volts, and runs super rich. I'm working on that, too.
The motor mods are:
Greddy intake with IACV delete, though I will be putting the IACV back on.
555cc injectors
T3/T4 turbo on top mount exhaust manifold
Synapse wastegate
Nistune ecu
Front mount intercooler and BOV
Full exhaust
A/C parts were all removed before I owned it, so no condenser, compressor, or evaporator.

I was going to be looking into the gauge sender next.

hanzbrady · 12-08-2016, 06:29 AM

My car did the same thing when I had a coolant leak under the intake, it could also be your water pump wearing out and not flowing enough water. My car would start to overheat in a drive thru, but would cool down if I revved the engine up spinning the pump faster.

moose4130 · 12-08-2016, 06:46 AM

The water pump crossed my mind, because it does sound like it's not getting enough flow. I was hesitant to pull it because it looks almost newer than other stuff on the engine, or different somehow, though I know that how it looks from the outside doesn't say anything for how it works.

All the small hoses under the intake are gone, the system flows to the radiator and heater core, and that's it. No small hoses to the IACV or TB.

jedi03 · 12-08-2016, 07:52 AM

im leaning toward tune...buddies 2j would heat up a lot under boost and cool back down when decelerating or idling...check fan and thermostat operation too tho

hanzbrady · 12-08-2016, 07:54 AM

Quote:

Originally Posted by jedi03

im leaning toward tune...buddies 2j would heat up a lot under boost and cool back down when decelerating or idling...check fan and thermostat operation too tho

He's having the opposite issue, cooling under acceleration and increased timing and heating up at idle.

*Nissan2nr22* · 12-08-2016, 10:29 AM

Sounds like bleeding issues. Ive bled so many SRs... IDK where to even start.

If I were you id keep track if you're losing coolant or not.
Jack it back up, turn it on, let the car get warm then turn the heater on. Get some thick gloves and start squeezing the hoses all throughout the car. Intake manifold hoses, heater hoses behind the engine, radiator hoses, just squeeze them tight, watch all the bubbles start flowing out of the radiator.

And when you bleed put a funnel in the radiator cap area, fill it and watch for bubbles, youll have to pinch off the overflow hose so it doesnt allow any water to it or out of it

Heres a video I Skimmed through and found

https://www.youtube.com/watch?v=nThsFGa1vuE

Also make sure your fans arent rewired backwards, some are reversible so you may be pushing air from engine to radiator

If none of that fixes it.........

Check for bad HG, bad timing, bad waterpump, bad thermostat, leak somewhere, better fans, shroud, better/bad radiator

jr_ss · 12-08-2016, 10:38 AM

Pressure test the system. I'm sure AutoZone has a pressure tester you can borrow.

kyral · 12-08-2016, 07:32 PM

Idk if i just read your post wrong, but it sounds like you dont have an aftermarket coolant gauge, and you asre going off the gauge on the dash. does it actually read hot on the dash gauge or does it just cool when youre driving?
does the car burp out coolant when you park it after a drive? are you losing coolant in anyway?
how do you know your overheating? if your temp gauge isnt reading max at any point youre not overheating, you might be overcooling just some thoughts.

If youre not burping coolant and the car gets really hot to the like max of the gauge but then cools when youre driving, im gonna +1 the water pump idea, and check that your e fans turn on

12-07-2016, 06:01 PM	#1
moose4130 Join Date: Nov 2016 Location: Dayton Ohio Posts: 14 Trader Rating: (0) Feedback Score: 0 reviews	sr20det redtop overheating, cools under acceleration I have searched, and tried what I have found. I purchased an s14 with sr20det swap already done. I discovered that it has an overheating issue, the temp spikes after 10-15 minute drive. The car has some heat, not super hot. In looking into this, I have replaced the thermostat, tried a different rad cap, topped off the overflow tank, and have had to replace the outlet pipe, because the bleeder screw was broken off in the old one. Since then, I have jacked the front end as high as I can and filled the system with a spill free funnel. I filled it with the car running and heater on, and after it was up to normal temp, I took the bleeder screw out for a second, coolant surged out, and I replaced the screw. I let the car run for a while with the heater on, and the gauge was roughly halfway up. I took the car for a quick spin to see if it helped, and it got hot, to the top of the normal range of the gauge. Upon returning, I discovered the gauge drops dramatically under acceleration. Any advice? The radiator is an aluminum radiator with electric fans that have a good shroud and dual fans.

12-07-2016, 08:21 PM	#2
jr_ss Post Whore! Join Date: Dec 2005 Location: Pa Posts: 6,056 Trader Rating: (34) Feedback Score: 34 reviews	Do you have the correct temp sensor for the gauge cluster? S13 and S14 use different sensors for the gauge. Next would be modifications done to the car/motor specifically. A full list. Do you have a wideband? If so, what is it reading at idle? __________________ My SR20VET

12-08-2016, 06:29 AM	#4
hanzbrady Zilvia FREAK! Join Date: Apr 2015 Location: Floriduh Posts: 1,168 Trader Rating: (4) Feedback Score: 4 reviews	My car did the same thing when I had a coolant leak under the intake, it could also be your water pump wearing out and not flowing enough water. My car would start to overheat in a drive thru, but would cool down if I revved the engine up spinning the pump faster. __________________ [email protected]

12-08-2016, 10:38 AM	#9
jr_ss Post Whore! Join Date: Dec 2005 Location: Pa Posts: 6,056 Trader Rating: (34) Feedback Score: 34 reviews	Pressure test the system. I'm sure AutoZone has a pressure tester you can borrow. __________________ My SR20VET

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12-08-2016, 06:20 AM	#3
moose4130 Join Date: Nov 2016 Location: Dayton Ohio Posts: 14 Trader Rating: (0) Feedback Score: 0 reviews	Unfortunately I don't have a wideband, but the narrowband is pegged at 2.5 volts, and runs super rich. I'm working on that, too. The motor mods are: Greddy intake with IACV delete, though I will be putting the IACV back on. 555cc injectors T3/T4 turbo on top mount exhaust manifold Synapse wastegate Nistune ecu Front mount intercooler and BOV Full exhaust A/C parts were all removed before I owned it, so no condenser, compressor, or evaporator. I was going to be looking into the gauge sender next.

12-08-2016, 06:46 AM	#5
moose4130 Join Date: Nov 2016 Location: Dayton Ohio Posts: 14 Trader Rating: (0) Feedback Score: 0 reviews	The water pump crossed my mind, because it does sound like it's not getting enough flow. I was hesitant to pull it because it looks almost newer than other stuff on the engine, or different somehow, though I know that how it looks from the outside doesn't say anything for how it works. All the small hoses under the intake are gone, the system flows to the radiator and heater core, and that's it. No small hoses to the IACV or TB.

12-08-2016, 07:52 AM	#6
jedi03 Nissanaholic! Join Date: Jul 2008 Location: albuquerque Posts: 1,786 Trader Rating: (8) Feedback Score: 8 reviews	im leaning toward tune...buddies 2j would heat up a lot under boost and cool back down when decelerating or idling...check fan and thermostat operation too tho

12-08-2016, 10:29 AM	#8
Nissan2nr22 Premium Member Join Date: Aug 2008 Location: USA Posts: 1,566 Trader Rating: (30) Rides Gallery: Nissan2nr22 Feedback Score: 30 reviews	Sounds like bleeding issues. Ive bled so many SRs... IDK where to even start. If I were you id keep track if you're losing coolant or not. Jack it back up, turn it on, let the car get warm then turn the heater on. Get some thick gloves and start squeezing the hoses all throughout the car. Intake manifold hoses, heater hoses behind the engine, radiator hoses, just squeeze them tight, watch all the bubbles start flowing out of the radiator. And when you bleed put a funnel in the radiator cap area, fill it and watch for bubbles, youll have to pinch off the overflow hose so it doesnt allow any water to it or out of it Heres a video I Skimmed through and found https://www.youtube.com/watch?v=nThsFGa1vuE Also make sure your fans arent rewired backwards, some are reversible so you may be pushing air from engine to radiator If none of that fixes it......... Check for bad HG, bad timing, bad waterpump, bad thermostat, leak somewhere, better fans, shroud, better/bad radiator

12-08-2016, 07:32 PM	#10
kyral Zilvia Junkie Join Date: Nov 2012 Location: wisconsin Age: 29 Posts: 447 Trader Rating: (7) Rides Gallery: kyral Feedback Score: 7 reviews	Idk if i just read your post wrong, but it sounds like you dont have an aftermarket coolant gauge, and you asre going off the gauge on the dash. does it actually read hot on the dash gauge or does it just cool when youre driving? does the car burp out coolant when you park it after a drive? are you losing coolant in anyway? how do you know your overheating? if your temp gauge isnt reading max at any point youre not overheating, you might be overcooling just some thoughts. If youre not burping coolant and the car gets really hot to the like max of the gauge but then cools when youre driving, im gonna +1 the water pump idea, and check that your e fans turn on