Antifreeze leak - ZR-1 Net Registry Forums

ralph92ZR1 · 07-25-2009

I would appreciate some advice. My Z is leaking antifreeze only when it runs, within 5 minutes, dripping below the lower cross-frame member. I have the front end up on jack stands, ran it, and cannot spot the leak. The telltale drip is on the underside cross member and I have used a mirror, light, etc to spot the source of the leak. I have checked all hose fittings, and to get to the hose entering the block, have removed the belt tensioner and serpentine belt. I cannot feel any leak around the water pump gasket or the water pump pulley, but have not removed the pulley itself. The small puddle inside the cross member is below the hose clamp on the hose entering the block but could also be below the water pump pulley-hard to tell. The pulley has no play in it and the mileage is only 19,000. So here are my questions:

Is it ok to run the engine briefly (5 minutes) without the belt to better view those areas??? WILL NOT ALLOW TO GO ABOVE 130 F.
Anything I have not thought of ???

Thanks for the advice

QB93Z · 07-25-2009

I had a coolant leak on my 1990 ZR-1 right after I bought it last year. I could not find it with a visual inspection. In ended up getting a coolant system pressure tester. The leak turned out to be from the radiator. The right end tank had small cracks. I replaced the radiator, all is OK now.

My symptoms were the same as you are describing. The coolant would puddle under the front cross member. A lot of the coolant system is "above" that cross member. The problem with finding slow leaks is that you have to be a operating pressure to track them down.

I would caution against prolonged running of the engine with the belt off. There really is no way to tell what engine temperature is without the coolant circulating.

I live about 2 hours from you in Westminster, MD. If you would like to meet up some where I would be happy to help you find the leak. I am available Sunday afternoon. Have Tester, Will Travel.

Jim
443-244-1347

secondchance · 07-25-2009

"I could not find it with a visual inspection. In ended up getting a coolant system pressure tester. The leak turned out to be from the radiator. The right end tank had small cracks. I replaced the radiator, all is OK now."

Same here.
You might be able to see through opening on the shroud with a flashlight depending on where it is cracked.

ralph92ZR1 · 07-26-2009

Thanks for the info and the offer but hesitate driving to Maryland with the leak. Will look into a pressure tester. Appreciate the response.

=D>

ZR1Vette · 07-26-2009

If your reference to 'cross member' is this item>>>

then another item to look at is the mesh covered hose.

I would check the clamps (eg tighten) for the hose that goes from the water pump to thermostat housing... hose looks like this>>

Also would carefully inspect the hose itself (since it is mesh covered might be hiding a small defect).

XfireZ51 · 07-26-2009

You can usually get a pressure tester on loan from Autozone or Advance Auto.

LGAFF · 07-26-2009

The downpipe hose that runs down behind the fan is a common place where the hose can rub through......happened to the 24hr endurance car, and my 92.

GOLDCYLON · 07-26-2009

Are the waterpump bolts tight? The pooling leads me to beleive this is the issue

07-26-2009

Pressure tester is the only way to verify where the coolant is coming from.

Disconnecting the fan belt is not going to help you solve where the leak is from, as it won't be building any pressure inside the system.

Locobob · 07-26-2009

Quote:

Originally Posted by Jeffvette

Pressure tester is the only way to verify where the coolant is coming from.

Disconnecting the fan belt is not going to help you solve where the leak is from, as it won't be building any pressure inside the system.

Jeff speaks the truth

Finding a leak with the engine running is no easy task.

07-25-2009	#1
ralph92ZR1 Join Date: Dec 2005 Location: Shillington, Penna. Posts: 67	Antifreeze leak I would appreciate some advice. My Z is leaking antifreeze only when it runs, within 5 minutes, dripping below the lower cross-frame member. I have the front end up on jack stands, ran it, and cannot spot the leak. The telltale drip is on the underside cross member and I have used a mirror, light, etc to spot the source of the leak. I have checked all hose fittings, and to get to the hose entering the block, have removed the belt tensioner and serpentine belt. I cannot feel any leak around the water pump gasket or the water pump pulley, but have not removed the pulley itself. The small puddle inside the cross member is below the hose clamp on the hose entering the block but could also be below the water pump pulley-hard to tell. The pulley has no play in it and the mileage is only 19,000. So here are my questions: Is it ok to run the engine briefly (5 minutes) without the belt to better view those areas??? WILL NOT ALLOW TO GO ABOVE 130 F. Anything I have not thought of ??? Thanks for the advice

07-25-2009	#2
QB93Z Join Date: May 2007 Location: Westminster, Maryland Posts: 3,684	Re: Antifreeze leak I had a coolant leak on my 1990 ZR-1 right after I bought it last year. I could not find it with a visual inspection. In ended up getting a coolant system pressure tester. The leak turned out to be from the radiator. The right end tank had small cracks. I replaced the radiator, all is OK now. My symptoms were the same as you are describing. The coolant would puddle under the front cross member. A lot of the coolant system is "above" that cross member. The problem with finding slow leaks is that you have to be a operating pressure to track them down. I would caution against prolonged running of the engine with the belt off. There really is no way to tell what engine temperature is without the coolant circulating. I live about 2 hours from you in Westminster, MD. If you would like to meet up some where I would be happy to help you find the leak. I am available Sunday afternoon. Have Tester, Will Travel. Jim 443-244-1347

07-25-2009	#3
secondchance Join Date: Aug 2006 Location: McLean, VA Posts: 3,726	Re: Antifreeze leak "I could not find it with a visual inspection. In ended up getting a coolant system pressure tester. The leak turned out to be from the radiator. The right end tank had small cracks. I replaced the radiator, all is OK now." Same here. You might be able to see through opening on the shroud with a flashlight depending on where it is cracked.

07-26-2009	#4
ralph92ZR1 Join Date: Dec 2005 Location: Shillington, Penna. Posts: 67	Re: Antifreeze leak Thanks for the info and the offer but hesitate driving to Maryland with the leak. Will look into a pressure tester. Appreciate the response. =D>

07-26-2009	#5
ZR1Vette Join Date: Dec 2007 Location: Reston, Virginia Posts: 930	Re: Antifreeze leak If your reference to 'cross member' is this item>>> then another item to look at is the mesh covered hose. I would check the clamps (eg tighten) for the hose that goes from the water pump to thermostat housing... hose looks like this>> Also would carefully inspect the hose itself (since it is mesh covered might be hiding a small defect). Last edited by ZR1Vette; 07-26-2009 at 09:30 AM.

07-26-2009	#6
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,685	Re: Antifreeze leak You can usually get a pressure tester on loan from Autozone or Advance Auto.

07-26-2009	#7
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,180	Re: Antifreeze leak The downpipe hose that runs down behind the fan is a common place where the hose can rub through......happened to the 24hr endurance car, and my 92. __________________ LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359

07-26-2009	#8
GOLDCYLON Join Date: May 2007 Location: Peoria, AZ Posts: 9,117	Re: Antifreeze leak Are the waterpump bolts tight? The pooling leads me to beleive this is the issue __________________ GOLDCYLON - 91 ZR-1 #2014 GOLDCYLON - 90 ZR-1 #2794, 4L60e (Formerly Schrade's) GOLDCYLON - 11 CTS-V Arizona State Director 91 WHITE/BLACK #2014. 380 P&P&PCed,Ported Heads, Jeal Long tubes, Corsa Exhaust/FIKSE FM-5s /LED TLs, LED Headlights, Front Wilwood 6 piston narrowlite calipers and rear Wilwood caliper street shop mod,CNCed Coolant Pipes,TPI Cvr,Filter cover,Stainless Bolts, DRM/DOM PROM /ZFDOC mod build #102,DRLs,BMAD with stainless Debris Screen,Coplan Air Blaster, Pioneer APP Radio 4,Brey-Krause HB,Sub Bar,Fire extinguisher seat mount,DRM Coilovers,LEDs everywhere,Compass mirror (orange),V1 DIC hidden display, Homelink sun visor, Carbon Fiber top x3 and APSIS Carbon Fiber interior, APSIS CF Steering Wheel/NAPA Leather, Banski trailing arms, Guldstrand front suspension,urethane bushings from Prothane (total suspension) ZFDoc drive shaft safety loop, raptor shift light (orange),AO engineering louver front plate, Console seat cushion, 96CE seats with black custom Sheepskins, ss billet catch can,Viper remote entry/alarm,Cragar Rear Louvers,LED side louver lights, Dewitts Radiator with SPAL fans and a Woods 160 T-Stat 90 RED/BLACK #2794. 4L60e Automatic Stage V by RPM Transmission, TCI Dedicated TCM, OBX Stainless Headers, Corsa Exhaust, SAN Secondaries and Haibeck PROM, Exotic Muscle Coil overs, LED Interior Lights, LED Tail Lights, LED Headlights, 94 Sport seats with black custom Sheepskins , Cragar rear louvers, GS Front calipers, Banski Trailing arms, APSIS Carbon Fiber steering wheel, Front and Rear Baer Eradispeeds, DRLs, Guldstrand front suspension,urethane bushings from Prothane (total suspension), Dewitt's Raditor with Dual SPAL fans and a Haibeck 170 T-Stat 11 RED/GREY CTS-V

07-26-2009	#9
Jeffvette Guest Posts: n/a	Re: Antifreeze leak Pressure tester is the only way to verify where the coolant is coming from. Disconnecting the fan belt is not going to help you solve where the leak is from, as it won't be building any pressure inside the system.