Transmission failing and radiator replacement

Tiny
SHELL2015
  • MEMBER
  • 2004 BUICK RENDEZVOUS
  • AWD
  • AUTOMATIC
  • 202,326 MILES
My car showed no signs of overheating then it shot to red and shut off. I left vehicle at shop asked to be told the issues. I was told it was cracked radiator and needed replacing. I said if that is the problem fix it. So when I picked up the vehicle I was told hey you need to have your transmission looked at I had to put eight quarts in. So transmission shop within five minutes said transmission done. The previous mechanic said it was urgent, but acted as if he had no clue what the problem was. And on top of it all the car continues to get hot after radiator and thermostat replaced. So I have two questions, 1. Would a leaking transmission fluid cause radiator crack or vice versa? And isn't a mechanic required to inform you before repairing all issues detected?
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Saturday, July 16th, 2016 AT 7:05 PM

10 Replies

Tiny
CARADIODOC
  • EXPERT
There is always a pressure relief valve in the radiator cap, but on a lot of models, the engineers at GM chose to move that to the reservoir. The cap, and the hose to the reservoir should be checked to insure excess pressure isnt being trapped. Second, GM has way more trouble with leaking radiators and heater cores than all other manufacturers due to their use of Dex-Cool antifreeze. Dex-Cool company says to replace it every two years to get the acids out and to replenish the additives that wear out. GM advertised it as lifetime coolant to make their cost of maintenance appear to be lower than that of their competitors, and unfortunately a lot of people believed the advertising and have had corroded radiators and heater cores as a result.

There are other things that can cause excessive pressure in he radiator, but again, that pressure relief valve should prevent that. It is much more likely the radiator was just corroded and ready to develop a leak.

As for somehow being able to tell you about everything else that is wrong, there is no crystal ball for that. They do take the time to look at tire wear patterns, and other signs of potential problems, but then you accuse them of trying to sell you parts or services you do not need. What the mechanic should not have done was to add transmission fluid without telling you or asking your permission. That was not something you approved or knew you needed, and I cannot help but wonder how you did not notice a slipping transmission. Eight quarts is at least half of what the transmission is supposed have in it.

I am not sure what you meant by "transmission done in five minutes". It takes longer than that to write up a repair order. To be that low there certainly should have been signs of a leak.

I will be back in a day or two to give you a better answer. My laptop crashed for the fourth time this year and my friend is working on it. I am typing this on a " toy" and it took over half an hour of frustration!
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Saturday, July 16th, 2016 AT 8:04 PM
Tiny
SHELL2015
  • MEMBER
What I meant (I am having frustrations with inputting in my cracked device so I understand frustration) was transmission guy had an answer for what was wrong in five minutes. I do not believe mechanics automatically going to rip you off, but my best friends father mechanic of forty years ( who is not available currently or I would have asked him) has quit numerous shops for their dishonesty. I am asking for only because I would not have had the repairs had I known transmission had issues. Also that is the funny thing, the transmission began to slip on drive home from a hundred mile drive one way, and I had the oil change maybe three or four weeks prior where they checked the fluid and was okay. Rarely did I see a spot of fluid on my driveway (which is blacktop hard to tell color) so I am confused about that. Also around a year ago had exhaust manifold water pump and a few other things replaced. I do not know and I am asking. Also is it not standard to flush the cooling system when you replace a radiator? My overflow has nasty stuff all in it. Thank you for your reply and I do not want to offend honest mechanics in any way.
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Saturday, July 16th, 2016 AT 8:21 PM
Tiny
SHELL2015
  • MEMBER
And I understand there is no crystal ball, but being short that much fluid seems enough cause to inform me there is an issue there before completing the radiator. I am not a mechanic, but I would presume serious problem if fluid that low.
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Saturday, July 16th, 2016 AT 8:26 PM
Tiny
CARADIODOC
  • EXPERT
I am so sorry, but I just typed with one finger for over half an hour, and for some reason the page disappeared and it is all gone! The frustration continues. I will be back after I buy yet another computer and I can see straight!
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Saturday, July 16th, 2016 AT 10:45 PM
Tiny
KEN
  • ADMIN
Hi, Its my opinion they shop should have seen there was transmission fluid in the radiator and that the cooler inside the radiator had let go, this can cause coolant to go into the transmission once the engine is shut off. How much coolant is hard to tell as well as transmission fluid inside the radiator. This repair is difficult to say because if they tell you the transmission is bad and it is not then they look bad, so this is a loose, loose situation when things go wrong, like they have, sorry about that.

It is not easy being a mechanic, this is one of those cases.

Best, Ken
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Monday, July 18th, 2016 AT 11:53 AM
Tiny
SHELL2015
  • MEMBER
The second shop told me a code came up quickly that it would need replacing but wouldn't recommend my wasting my money. The first shop, I believe should have talked to me about the lack of transmission fluid but did not. I would have had the transmission diagnosed before fixing the radiator had he informed me of that issue before repairing. I really am wondering is it at all possible he wouldn't realize the transmission had an issue while diagnosing a cooling system? And why would it still be overheating?
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Monday, July 18th, 2016 AT 3:05 PM
Tiny
KEN
  • ADMIN
I would check to see if the cooling fans are plugged in, here is a guide that can help you with that part of the problem.

https://www.2carpros.com/articles/engine-overheating-or-running-hot

also, you might have blown a head gasket, here is a guide to hat as well

https://www.2carpros.com/articles/head-gasket-blown-test

Best, Ken
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Monday, July 18th, 2016 AT 3:11 PM
Tiny
CARADIODOC
  • EXPERT
Well, I'm back on a borrowed 'puter. I forgot most of the great and wondrous things I was going to share, other than in my extended community of around 100,000 people, we have mostly very reputable shops. I worked for a very nice family-owned Chrysler dealership. There is also a fine GMC dealership, and a good Cadillac dealership. We used to have a great Ford dealership and a very honest import dealership. All of those would borrow service manuals back and forth, and help with fixing each others' trade-ins. Unfortunately the Chevy dealership is owned by the biggest crook in the county, and he bought up the Ford and import dealerships, and now they're just as bad. Due to their wide-spread reputations, buyers go north 15 miles or south 30 miles to other dealerships if they are emotionally-involved with those brands. Some of my former students lost their jobs because those dealerships aren't selling any cars and people aren't coming back for service.

We also have some really good independent shops. There was one notable exception and I noticed a few nights ago he is out of business. Unfortunately anyone who went there now assumes the entire industry is full of dishonest people.

After being asked to look at numerous repair bills during nine years of teaching, in almost every case the owner's dissatisfaction boiled down to poor communication, (which mechanics aren't good at), and / or unreasonable expectations. When you asked why you weren't told about the transmission problem, that hasn't reached the level of unreasonable expectations on your part. Rather, the problem usually is the result of lost communication or poor translation between the mechanic, who understands your vehicle, the service advisor, who does not understand cars but is expected to take what he heard from the mechanic and interpret it into something he thinks you will understand, and you. Just like with doctor to nurse to you, or accountant to secretary to you, you know the story is going to change each time it passes through another person. That is not an intent to deceive or rip you off, but it DOES end up in frustration a lot.
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Tuesday, July 19th, 2016 AT 6:20 PM
Tiny
SHELL2015
  • MEMBER
What I am basically asking is did my transmission leaking possibly cause radiator crack? Also as I am sitting here, my car ( which I was driving home with heater blasting due to it getting hot --- but parked around 2:30 pm) is making faint gurgle noises 5 hours after parking it. Why would that happen?
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Tuesday, July 19th, 2016 AT 7:44 PM
Tiny
CARADIODOC
  • EXPERT
Gurgling in the heater core, (in the dash), is caused by air in the cooling system. That should work its way out fairly quickly. If it continues, or if there is bubbling in the reservoir, I d be more worried about a leaking cylinder head gasket. That is an expensive repair, but a pretty common one on any car brand.

After thinking about this some more, I suspect the logical conclusion might be the transmission cooler, which is usually just a pipe running through part of the radiator, corroded through, and the sudden increase in pressue caused the radiator to pop. Had that happened slowly over, say an hour or more, you would have noticed the transmission slipping. I think the cooler let go abruptly. That would explain why the overheating showed up right away, AND the transmission was so low but you didn t have time to observe the additional symptom.

Naturally you couldn t tell the mechanic the transmission was low, because you didn t know it. An experienced mechanic should have put two and two together, but a lot of them have never run into this.

One good peice of news, I suppose, is GM usually runs transmission fluid through their coolers at more than 15 pounds of pressure, so it s higher than the coolant. When the transmission cooler leaks, that higher pressure can damage the radiator. Some manufacturers run the transmission fluid in the cooler as low as 5 pounds, so when there s a leaking cooler, coolant gets forced into the transmission. If you catch it right away, you can flush the transmission and save it, but often the symptoms take days or weeks to show up to the point you realize a serious situation is occurring. That can result in a failed transmission, which is a real lot more expensive than a radiator.
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Tuesday, July 19th, 2016 AT 8:57 PM

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