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Temps are seeing 240-250 just under red when I'm at idle. They drop to the middle when I pop it into neutral and raise the rpms up. when I shut the car off I can hear the coolant gurgling and coolant seems to be spilling from the refill resevior but it doesn't come up top it comes from below in that area.
I've bleed the system 4 times and I haven't looked underneath that panel yet but what do you suspect before I dig deeper?
Btw I'm able to drive city and highway no problem. It shoots that high when the rpms are low. All other hoses are fine, water pump looks good. Just didn't know a canister can give me problems (if that's what it is). Not sure how air is getting in there it seems..
Are you keeping an eye on your coolant level? You have a leak and it looks to be in the overflow piping. If there is a leak in that pipe, coolant will be pushed out when hot and will never return, because the leak breaks the vacuum seal needed for it to be pulled back into the radiator during cool down (a normal function of the system).
Are you keeping an eye on your coolant level? You have a leak and it looks to be in the overflow piping. If there is a leak in that pipe, coolant will be pushed out when hot and will never return, because the leak breaks the vacuum seal needed for it to be pulled back into the radiator during cool down (a normal function of the system).
Yeah that's what I was thinking.
Yeap been checking the level when it's cool, been taking the rad cap off and it's always full. I've bleed the system with the motor on method and bleed with motor off method. What are my options?
Not sure the exact spot it's leaking from. Don't really know the construction underneath the panels but im a cheap & quick *** and hoping there a way of n!gger rig it.
Thanks
Last edited by 93Euphoria; 02-17-2016 at 10:15 PM.
What do you guys mean by swapped? It's the stock one. It's all original and this might be bad because of my accident. The curb
The very first line, right under the radiator cap, where does that lead to? Under the battery or to the throttle body?
I seriously doubt a cracked reservoir would cause the issues you describe. Mine cracked when I wrecked, still cracked, hold no coolant what so ever. I have zero coolant systems issues. If revving the engine from idle cools it down noticably and quickly, you have air in the heads.
A quick way to do that is to route the steam line to the upper radiator port (just under the cap) and the reservoir line below it, as opposed to the correct way: reservoir line goes above the steam line.
If they are indeed correct, I'd check the rad cap and make sure it's holding the correct pressure before it releases. If that's right and good, check the weep hole for leaking. It may be leaking, but many times the hot coolant evaporates before making a noticable puddle or drips.
The very first line, right under the radiator cap, where does that lead to? Under the battery or to the throttle body?
I seriously doubt a cracked reservoir would cause the issues you describe. Mine cracked when I wrecked, still cracked, hold no coolant what so ever. I have zero coolant systems issues. If revving the engine from idle cools it down noticably and quickly, you have air in the heads.
A quick way to do that is to route the steam line to the upper radiator port (just under the cap) and the reservoir line below it, as opposed to the correct way: reservoir line goes above the steam line.
If they are indeed correct, I'd check the rad cap and make sure it's holding the correct pressure before it releases. If that's right and good, check the weep hole for leaking. It may be leaking, but many times the hot coolant evaporates before making a noticable puddle or drips.
Had one of my master techs look at it and the high speed fans aren't coming on. I did the paper clip trick and they come on when I turn the key on.
He said I should jump the high speed fans on direct and I'm not sure how to do that. He speaks Spanish and does not speak English very well so I would appreciate it if someone could explain how to run the high speed fans on direct for now. The high speed fans aren't coming on at 235. Only low speed comes on.
I'm not good at reading schematics:
Last edited by 93Euphoria; 02-18-2016 at 06:11 PM.
Had one of my master techs look at it and the high speed fans aren't coming on. I did the paper clip trick and they come on when I turn the key on.
He said I should jump the high speed fans on direct and I'm not sure how to do that. He speaks Spanish and does not speak English very well so I would appreciate it if someone could explain how to run the high speed fans on direct for now. The high speed fans aren't coming on at 235. Only low speed comes on.
I'm not good at reading schematics:
The easiest way to do what you are asking is to jumper pins 85 of both fan relays together. However, I think you should hook up a Data log and see what the PCM is seeing.
If the 2nd fan comes on when you engage maintenance mod, everything is working as far as the fan engagement side of things. So this leaves a bad signal to the pcm being the issue. Possibly a bad coolant sensor on the water pump. A Data log would show this.
The easiest way to do what you are asking is to jumper pins 85 of both fan relays together. However, I think you should hook up a Data log and see what the PCM is seeing.
I have no idea how to do this. Could you please explain in better detail how to do this step by step? Do I need to splice into wires and cut them and run? I honestly am just a part changer and need a dummy explanation! As far as the datalog my shop does not have it for OBD1. So I'm SOL on that part. I'll try the temp sensors. But I would still like to know how to run high speed fans direct.
I have no idea how to do this. Could you please explain in better detail how to do this step by step? Do I need to splice into wires and cut them and run? I honestly am just a part changer and need a dummy explanation! As far as the datalog my shop does not have it for OBD1. So I'm SOL on that part. I'll try the temp sensors. But I would still like to know how to run high speed fans direct.
Thank you for helping me out so far.
I'll start with a basic explanation of how a few things work.
First are the relays. Relays are electromagnetically actuated switches, they all have two parts. 1 side is a switch and the other is an electromagnet. The electromagnet activates the switch. The relay pin locations are marked with a small schematic printed on the side or top and sometimes with small markings next to each pin on the bottom.
Next is how your car is wired up. You have 2 fans and each fan is actuated via a relay. Both sides of the relay receive 12V positive continuously (pins 30 and 86 of each relay respectively), this means they are ground seeking.
The switch side of each relay seeks ground through each fan. When the switch is closed (in the "on" position), it connects to ground through the fan. So it goes 12V+ -> in pin 36 and out pin 87 of relay switch-> fan -> ground.
The electromagnet of each relay also receives 12V positive continuously. It too is ground seeking, that ground is controlled via switch in the PCM. The PCM will activate the ground switch at it's programmed Coolant Temp. So it goes 12V+ -> in pin 86 and out pin 85 of relay electromagnet -> PCM switch -> ground.
Both 12V+ sources are fed through different fuses, but they both feed both fans. So one 12V+ source is fused via Fusible Link C and feeds BOTH Fans through the switch side of each Relay pin 30 (parallel wiring); this is the high current side of the relay. Another 12V+ source is fused via 10Amp fuse (located in the fuse/relay box under hood with the Fan Relays) and feeds BOTH electromagnetic sides of each relay pin 86 (parallel wiring), this is the low current side.
The PCM receives it's Coolant Temp via a sensor on the Water Pump. The sensor is a variable resistor that will fluctuate it's resistance based on how hot the sensing element gets. The cooler the sensor is the higher it's resistance (-40°f is >100,000 Ohms) as it gets hotter the resistance drops accordingly (212°f = 177 Ohms). See Shbox for what each temperature to Ohms resistance you are looking for. When you get to that link press Ctrl+F and type "Testing the ECT", then enter and it should take you to the ECT Chart.
This is how everything works together....
The Coolant Temp Sensor (or Engine Coolant Temperature Sensor - ECT), measures coolant temp and sends that information to the PCM via a resistance value. The PCM then takes that information and engages a switch within it (to one or both relays depending on the Tune and Temperature of Coolant) that allows current to flow through the electromagnet inside of each relay. When Current is flowing through the electromagnet of the relay, it physically pulls on the switch in the Relay causing the switch to close the circuit to the Fans, making the fan(s) run and draw air through them.
If you can command the PCM to turn on the fans, that tells you that everything within that system is working as it should; BUT only when commanded. If only the primary fan comes on automatically, that really only leaves one thing that can cause your issue; the Coolant Temp Sensor on the Water pump is going bad. I stress really because there's other things involved here. The PCM also looks at vehicle speed, A/C Clutch status, throttle position, and what the transmission (if Auto) is doing before engaging the switch to either relay.
Usually if the AC is on, both fans come on (I'm not 100% sure on this for your vehicle) regardless of Coolant Temp.
The fans also will not come on if the vehicle is over 36 mph (stock tune) as the airflow through the radiator at 36 mph is the same airflow that both fans on will give you. That means having the fans on is a waste of energy at or above 36 mph. So the PCM will (well should...) NOT engage the switch to the relays above 36 mph regardless of Coolant Temps or AC status. Caveat: there are scenarios that the PCM will engage both fans even at high speed but those temps are much higher. It's a fail safe. Basically, if the car reaches a certain coolant temp, the PCM will turn them on no matter what other inputs it receives.
I'm not sure what the TPS and Trans information does exactly with the Cooling fans in the PCM, if anything. But it's noted on the Schematic you provided.
So what you should do is hook up an Ohmmeter and verify the ECT on the water pump is showing the proper resistance for it's actual coolant temp (fan 1 on should read less than about 250 Ohms (I forget the actual fan 1 on temp setting for a stock tune, but you can reference that SHbox site I linked above for the correct readings throughout the temp range), fan 2 on should read less than 177 Ohms). If you hook up an Ohmmeter and never see less than 177 Ohms, the 2nd fan didn't come on, and the coolant is boiling, the sensor is bad.
What you can do to run a manual fan switch is run a switched wire from the dark green and dark blue wires from the under hood fuse box (you'll have to cut and splice into the wires to do this) to ground. Done this way, the fans will come on when you engage the switch you installed, but will turn off with the key (assuming they actually do turn off now with the key turned out of the RUN position: how it should be). Or you can cut and splice the dark green and dark blue wires together, that will make both fans turn on when the PCM engages the low fan; no switch needed. Or you can find a way to fit a jumper of some sort (you'll need to be creative) between pins 85 of each fan relay together, no splicing required and no switch needed either. That too should command both fans on when the PCM engages fan 1. But doing it the last way can stretch out the plugs in the relay box and can lead to connection issues once the jumper is removed, causing it's own set of problems.
Having said that, when you jumper-ed the ALDL port (OBD1) to maintenance mode (fans come on), did you confirm that both fans are actually coming on? Or did you just listen for a fan noise and assume they were both on?
What I would do before splicing or moding anything is verify both fans do come on in maintenance mode. I'd also verify the coolant system is properly bled. Then I would verify coolant temps by running the engine with an Ohmmeter back pinned to the ECT sensor plug (the ECT needs to be plugged in with the engine running); another option is to turn the engine off, disconnect the ECT plug, and measure the Ohms between the two pins in the sensor on the water pump. Then, while the engine is running and the temp gauge (on dash) is showing about mid mark (the Ohmmeter should read less than 300 Ohms), I'd jumper the ALDL plug into maintenance mode. That SHOULD make the temps drop back down. IF both fans are on and the temps don't drop, you have a coolant flow issue.
An easier way to do all this is to get your self an ALDL cable (12 pin OBD1 style to USB adapter cable) for $60. If you have a laptop, download and install Scan9495.exe (by Gary Doug) and EEHack (by Steveo_); both are free programs made specifically for the LT1, a google search for those programs or their creators will get you to the download links. Then you can datalog your car and see everything the PCM is seeing in real time, you could also share those logs with us so we can help you better. If you don't have a laptop, go to craislist and get a cheeap one, it doesn't have to be fancy. As long as it has a USB port and runs Windows XP or newer you're good to go; having a working battery is a big plus though.
I'd like to provide a little more information regarding the cooling system of the engine. This isn't all LT1 specific, but should help with troubleshooting cooling issues. This isn't just for the OP, but for anyone that can use the info.
Coolant and Water have different boiling temperatures. Water is better at absorbing heat, but it's corrosive and isn't a very good lubricant and it has a lower boiling point. Coolant raises the boiling point and provides protection against corrosion while also being a better lubricant within the cooling system, but it doesn't remove as much heat.
A 50% mix of Water/Coolant has a boiling point 226°f at sea level, this will be lower at higher elevations (more specifically density altitudes or ambient air pressures). The boiling point raises with pressure.
The LT1 runs at temperatures (stock) that exceed the boiling point of the coolant. But, the cooling system is closed and this allows the system to build up pressure. When you add pressure to water and coolant the boiling point also rises. At 16PSI the boiling point of 50% water/coolant is raised to 267°f. The regulator to the amount of pressure the system will reach is the radiator cap. Stock LT1's come with 18PSI radiator caps, that pressure is maintained by a spring on the cap.
Over time the spring weakens and it will not be able to maintain the stock PSI in the system. As the spring weakens the PSI in the system can also go down, if that happens the boiling point also goes down. When the pressure in the system gets low enough to allow the coolant to boil at normal operating temperatures, it will turn the coolant into steam (gas/air). From there it's a run away steam/air conversion and the only way to stop it is to turn off the engine and let it cool and service the cooling system (fill and bleed).
There are other ways to cool the engine with it running, but it's not recommended unless you know what you are doing. I've had engines go way passed the red on the dash, in those cases I don't turn off the engine (it's likely a bust anyway). Instead I get the engine to a fresh water source right away, open the radiator cap (this is very dangerous and can cause severe burns and bodily harm, including to your face and lungs), and with the engine still running I start to add fresh water (coolant is a waste at this point). I add it somewhat slowly. The purpose here is to cool the engine down internally, it will steam out the fill cap as you're filling the radiator and that's o.k. Keep adding water until the temps come down to normal operating temps again, then turn off the engine. I've saved many engines doing this without any side effects, engines that have continued on for 50-100K miles after words. Using this method allows the metal in the engine to cool down quickly without cracking but also keeps it from warping from being too hot too long. Again, this is only recommended for situations where the engine got so hot it's likely (very likely) it's already going to need major repairs.
Never ever ever spray the engine down with water when it's hot (even at running temps) with the engine off. This is very likely to crack something. If the engine is at operating temps AND running, it's usually safe to wash it. I've done this many times and have never had an issue, but do so at you're own risk. This also only applies to liquid cooled engines. If the engine is overheating and running, don't spray it down. It'll likely crack something. Although, it should be safe to spray the radiator down in any scenario.
I'm mentioning this because if the radiator cap is weak and not allowing the system pressure to build up, the coolant will boil at normal operating temps. The boiling will force coolant out of the system (via the reservoir overflow line just under the radiator cap, there's a reason it's located right there on all engines) and displace that coolant with air.
OP, it is possible that the cap is bad and everything else works exactly as it should. But the system is boiling before the engine get's hot enough to command on the 2nd fan. By then, it's a run away effect and only gets worse until you can service the coolant system properly again.
02-17-2016, 09:24 PM
Coolant flow problem 
