Coolant leak & mixing with oil

nick124 · 09-18-2012, 06:34 PM

I just purchased my '91 Supra turbo yesterday and am very excited about it. I got it for a good price and it is a bit of a fixer-upper. That being said, It is puking coolant and the oil is chalky when I checked it. I took it to a local shop (because they offer free inspections and I don't have a hoist myself) and they showed me what we think is a leaky timing belt cover gasket. This of course is not coming from the top, plastic section, but rather the bottom section. Of course they said it was a 5 hour fix and I am hoping to do it myself. I am in school however and may not actually have the time.

Is this a common issue? Has anyone here had this problem and/or fixed it themselves? I am trying to find out as much information as I can and I am obviously very new to the forum, but I hope to be an active member.

Thanks.

cre · 09-19-2012, 02:30 AM

I'm sorry to say exterior leaks are the least of your worries. Oil and coolant cross contamination is indicative of a blown head gasket. Refer to the FAQ section for threads about BHG or blown head gasket for details on the process of how to repair it. It's not a quick or easy job for a novice... It's not a cheap job if you pay a shop to do the whole thing.

Here's a starting point:
http://www.toyota-supra.info/forums/...-symptoms.html
http://www.toyota-supra.info/forums/...ir-w-pics.html

nick124 · 09-19-2012, 03:17 AM

This is what I thought when I checked the oil. However, The exhaust is not white at all and there is no sweet smell. Also, the car apparently has a metal HG with ARP studs torqued correctly. I know that the MK3 had major HG problems with the factory torque specs.

cre · 09-19-2012, 09:00 AM

I may be misunderstanding part of your description of the problem... What do you mean the oil looks "chalky". Chalk, soft white stone, used on black boards a couple decades ago?

Oil leaking near the timing belt is not going to affect your coolant in any way. There are a few places where that oil could be coming from: Cam seals, oil pump seal, front main seal, or if the head gasket job wasn't done by the book the lower rear timing case/block union FIPG wasn't applied.

A head gasket doesn't have to leak anything into the cylinder to allow oil and coolant to leak into one another's circuit. The only other ways for the two to mix as you're describing are a seriously cracked head or a seriously cracked block. Just because there's a MHG and ARP fasteners it doesn't mean the job was done right...

Your new best friend: http://www.cygnusx1.net/Supra/Library/TSRM/MK3/

nick124 · 09-19-2012, 01:42 PM

Thanks for your replies and sorry for not making myself clear. It is actually coolant that is leaking from the seal, not oil. I am not certain of what the gasket is actually called, but they described it to me as the lower timing belt cover gasket that the COOLANT is leaking from. The mechanic worked at Toyota in his earlier days and right after discovering where the coolant leak was he checked the oil and was not surprised to see that coolant had mixed with the oil.

To help verify that it is not the HG (which the mechanic said it was not), my buddy is coming over later today with his compression tester.

Again sorry for the confusion and I will have more information to post later today.

907mge · 09-19-2012, 03:33 PM

Like cre said the coolant and oil systems are separate. Even if it is your coolant is leaking it should not be mixing with the oil. Inside the head are coolant and oil passages the are separated by the head gasket. Again like cre said there doesn't have to be a leak into the cylinders to have a bhg. Therefore your compression may still read normal.

09-18-2012, 06:34 PM	#1
nick124 Stock Join Date: Sep 2012 Location: Brantford, Ontario Posts: 10	Coolant leak & mixing with oil I just purchased my '91 Supra turbo yesterday and am very excited about it. I got it for a good price and it is a bit of a fixer-upper. That being said, It is puking coolant and the oil is chalky when I checked it. I took it to a local shop (because they offer free inspections and I don't have a hoist myself) and they showed me what we think is a leaky timing belt cover gasket. This of course is not coming from the top, plastic section, but rather the bottom section. Of course they said it was a 5 hour fix and I am hoping to do it myself. I am in school however and may not actually have the time. Is this a common issue? Has anyone here had this problem and/or fixed it themselves? I am trying to find out as much information as I can and I am obviously very new to the forum, but I hope to be an active member. Thanks.

09-19-2012, 02:30 AM	#2
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	I'm sorry to say exterior leaks are the least of your worries. Oil and coolant cross contamination is indicative of a blown head gasket. Refer to the FAQ section for threads about BHG or blown head gasket for details on the process of how to repair it. It's not a quick or easy job for a novice... It's not a cheap job if you pay a shop to do the whole thing. Here's a starting point: http://www.toyota-supra.info/forums/...-symptoms.html http://www.toyota-supra.info/forums/...ir-w-pics.html __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

09-19-2012, 09:00 AM	#4
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	I may be misunderstanding part of your description of the problem... What do you mean the oil looks "chalky". Chalk, soft white stone, used on black boards a couple decades ago? Oil leaking near the timing belt is not going to affect your coolant in any way. There are a few places where that oil could be coming from: Cam seals, oil pump seal, front main seal, or if the head gasket job wasn't done by the book the lower rear timing case/block union FIPG wasn't applied. A head gasket doesn't have to leak anything into the cylinder to allow oil and coolant to leak into one another's circuit. The only other ways for the two to mix as you're describing are a seriously cracked head or a seriously cracked block. Just because there's a MHG and ARP fasteners it doesn't mean the job was done right... Your new best friend: http://www.cygnusx1.net/Supra/Library/TSRM/MK3/ __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

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09-19-2012, 03:17 AM	#3
nick124 Stock Join Date: Sep 2012 Location: Brantford, Ontario Posts: 10	This is what I thought when I checked the oil. However, The exhaust is not white at all and there is no sweet smell. Also, the car apparently has a metal HG with ARP studs torqued correctly. I know that the MK3 had major HG problems with the factory torque specs.

09-19-2012, 01:42 PM	#5
nick124 Stock Join Date: Sep 2012 Location: Brantford, Ontario Posts: 10	Thanks for your replies and sorry for not making myself clear. It is actually coolant that is leaking from the seal, not oil. I am not certain of what the gasket is actually called, but they described it to me as the lower timing belt cover gasket that the COOLANT is leaking from. The mechanic worked at Toyota in his earlier days and right after discovering where the coolant leak was he checked the oil and was not surprised to see that coolant had mixed with the oil. To help verify that it is not the HG (which the mechanic said it was not), my buddy is coming over later today with his compression tester. Again sorry for the confusion and I will have more information to post later today.

09-19-2012, 03:33 PM	#6
907mge 20psi boost Join Date: Dec 2009 Location: Harrisburg Posts: 759	Like cre said the coolant and oil systems are separate. Even if it is your coolant is leaking it should not be mixing with the oil. Inside the head are coolant and oil passages the are separated by the head gasket. Again like cre said there doesn't have to be a leak into the cylinders to have a bhg. Therefore your compression may still read normal.