Rundown: New motor, been running since October, sat from Dec-Mar, was driving fine before this happened. Put the RA Teflon coated coolant seals in the motor when I was building it. I built it with the help of a friend who has helped several on this forum (SgtBlue being one of them) rebuild his motor and has rebuilt his own several times to inspect the wear on the internal parts after long seasons on the track.

A few weeks back my idler pulley decided it no longer had the wheel to live and spun its bearing while I was out driving around. The car overheated (I believe I saw 120C on the PFC) and I promptly pulled into the nearest parking lot and called a tow company to get me home.

I got the replacement pulley on and topped off the coolant system as I had lost some by opening the system before it had fully cooled (but after it was well below boiling). The car started up and ran same as before with no smoking and no visible champagne bubbles in the coolant system.

Now after I let it idle for roughly 10 seconds the low coolant level buzzer starts sounding and I can't figure out why. My thought is that the sensor is bad and I'm going to order a replacement on Tuesday, but I would love to drive the car this weekend (supposed to be getting it fully tuned after making it through the break in!) and this stupid buzzer won't shut up! I'm very leery of unplugging the sensor from the harness altogether (despite the factory gauge not working) on a fresh motor while I'm supposed to be tuning just in case its actually trying to tell me something (not sure what that would be since the coolant is full.

Oh yeah, the previous owner removed the coolant overflow tank so there's no concern that coolant is passing into the overflow tank and not coming back.

I've already searched quite a bit and am looking for advice for the long weekend. Disconnect the sensor, drive it and risk it? Leave it parked and cancel the tuning session (not something I want to do since the tuner is coming into town already and I only have to buy him food instead of paying him like I normally do). Just tolerate the stupid noise? Seeking the advice of more experienced individuals, what would you guys do in my situation?

Relevant mods: Pineapple streetport, single turbo, PFC/commander, koyo rad and FMIC,

Questions? Answers? Haters that tell me I should scrap the rotary and I should've had a V8 (only kidding...)? All advice welcome.

 

Ok... so I tried disconnecting the plug just to see what would happen, buzzer won't shut off. The speaker is in the instrument cluster and I don't want to unplug that clip as it also powers the oil pressure gauge and fuel level gauge.

Advice?

 

Why the heck is your coolant reservoir deleted???

The sensor works through ground, unplugging is the same thing as it sensing an air pocket...which is the whole reason it's buzzing in the first place.

Install a coolant overflow and burp the air out of your system.

 

I'm confused as well. How do you "delete" the overflow tank? Where is the coolant now going when the pressure cap lets some through?

 

Sorry, not deleted, just not hooked up in any way as to make it functional. If I had a dollar for everytime I asked myself why the previous owner did something I would probably have enough money to fix every strange thing he did wrong. Unfortunately I overpaid for someone else's project and I'm still paying for it. I'll get that done tomorrow. Thanks guys.

 

Yea, hook that back up and fill/burp the system and then see if you still have the issue. Have you been driving like that for long and it hasnt been a problem thus far? The coolant system will release fluid into the reservoir and then suck back in as heat/pressure changes, so not having that is probably your problem.

 

Those idler pulleys are nothing but trouble

 

If your confident that the coolant level is where is should be, and no air is in the system, try following the sensor wire back from that first connector. IIRC, it goes back under the alternator toward the left/driver's side of the block.

 

You likely dont have a full coolant system (air in the system). Follow this procedure several times until it is full:

Disconnect the throttle body coolant line. This will allow air to escape when you pour in coolant. Remove ast and filler caps. Fill ast. Cap it. Fill filler tube slowly. Cap it. Re-connect Throttle body coolant line. Run the car for a few minutes.

Let it cool. Repeat until ast and filler neck stay full

Reconnect your overflow tank.

 

You really need a properly functioning overflow system.

However, if it is getting tuned this weekend just burp the system really well and keep the fans running all the time(Should be on the dyno anyway). Ground the wire for the sensor so it will shut up and just keep an eye on the PFC coolant readings. Once it gets to 100C just shut the car off and leave the fans running.

 

Its been driving as is for a while with no problems. But its only been to ~4500 rpm and no more than 8ish lbs, strictly break-in miles so nothing hard.
Probably just gonna bite the bullet and pay the tuner to come back some other weekend so I can get this all sorted out. There's enough other little things I can do on the car in the mean time anyways.
Jim, you're right, the line does go back that way, I've followed it as far back as the harness.
Thanks for all the replies everyone, got me headed in the right direction. Now to go watch some Pro-Solo autocross then work on the car.

 

Hey Kyle,

Did you resolve your coolant issues? BTW, I removed my Kirk rollbar and it is for sale. Do you still want it?

James

 

Didn't get a chance to work on the car today and I want to order a few little things anyways so I'm going to have to wait until Tuesday. I do, don't suppose you brought it down did you? I saw your car out at the course today but when I came down to look for you nobody was there. I'll be back out tomorrow and I'll talk to ya then.

 

Another question for you guys, do you just hook up the coolant overflow reservoir to the place on the radiator that originally had the hose going to the AST (also removed by the PO). Also, where is the pressure cap located on the cooling system that controls whether the coolant flows to the overflow tank or not?

Edit: I think I answered my own question, its on the FC filler neck that you swap out for when doing the AST delete, correct? No wonder I didn't see any sane spot to hook the line up to when I was looking this morning. The motor doesn't have one on it...

 

what brand is the idler pulley?

 

Correct. Call Ray Crowe at Malloy and ask for the AST delete kit. He'll send you everything, including a new cap. Once installed, the hose from the bottom of the radiator is deleted. Plug it properly. The old nipple on the filler neck/t-stat housing is similarly plugged. The overflow hose then runs from the new FC filler neck to the overflow bottle. Mine's been deleted about 4 years with no issues.

 

Same question here....

 

I'm not sure if FCs anf FDs are the same about this sensor but when that happened to my FC was because the actual sensor was bad. What I did was to put a plug on the radiator to seal the hole and ground the wire. buzzer and light when away.

Hope that helps