I took our blazer to what is supposed to be the best mechanic in town several months ago. My wife was having some engine shutoff problems she stated & I had observed radiator fluid dripping from somewhere under the engine, but I could not tell from where exactly. I also observed liquid in the cavity of the intake manifold. I also observed that the fuel gauge was bouncing all over the place. I also observed an extremely strong anti-freeze like smell coming out when I just happened to turn the heat up momentarily on this 99 chevy LS blazer with V-6 & four wheel drive. We have been back to the mechanic & spent over $1000. Unfortunately although I used to do pretty much all the vehicle work I cannot seem to do any of it these days on the modern vehicles like this one. First the mechanic stated it was a bad computer. Then he said it was frayed wiring. Then he said good news, no, it is the alarm system & no one can work on it(they don't like working on them here & it was installed new when we lived in another state before I was transferred here & then canned) here. So they disconnected the alarm & then the door locks would not work, the remote entry would not work, etc. So I said something about that & he reconnected the remotes, locks, etc. left the alarm off & it burned the driver's side mirror via the warmer. They said the could locate no leak. I observed no further problems with engine shutoff (I had been out of town for several months). However, I still observed leakage so I took it back to them. Then they stated they found the leak, it was the intake manifold gasket & they replaced that. Then I still observed leakage & fluid missing from the overflow reservoir & what fluid was there was Green rather than Orange so I took it back yet again as they are supposed to be the best in town & only I know to take it to other than the dealer & you know the dealers these days. This time they kept it for a few days & said they finally found the problem, the water pump was going bad & they replaced the water pump. They wanted to replace it with a DELCO pump at a high price, but I balked about the price of the pump (not the labor) relative to the last time I replaced one & the fact that they usually seemed to have lifetime warrantees on them. So they then came back & said Delco had a lifetime warrantee on theirs to so we were in good shape & I thought, great we finally have this tiger in the cage. However, since then I have observed over the past few months that the reservoir has going down again extremely slowly to nearly nothing & we are still getting the bouncing fuel gauge now that we have used more than a half tank of gas & also we are still getting that horrible smell when the heat is on now that we are having to use the heat regularly due to cold weather. This Blazer looks brand new otherwise or close to it, is in great shape, only has about 70k some odd miles, & runs good otherwise with reasonable economy as best can be for this vehicle. Does anyone have any idea what this could be & hopefully I can fix it as my wife is now on me for taking to these guys & now wants me to take it to the dealer. Thanks in advance.

 

Maybe your mechanic is the best in town on Fords. I'm no expert, and haven't experienced your problem personally, but I would first consider that my heater core might have a leak. Just a thought. To others in the forum...would a radiator pressure test kit locate the leak if it is in the heater core?

EDIT: Here's a short thread to get you started. https://blazerforum.com/forum/2nd-ge...ater+core+leak

 

RockP2,
I knew I had that coming to me after I re-read my post. They are supposed to be the best on American & older vehicles period. The manager/owner that I always talk to prefers GM/Chevy. I do understand exactly what you are referring to though without getting longwinded about it. Yes, my thought is the core as well & has been. However, on about the third trip back when they kept it for several days that was the whole idea is to allow them to run a pressure test on it for a long period since they kept saying they could find nothing & there was no leak. Then they found the problem with the pump. I have replaced the core back in the 60 & 70 model vehicles & had no problem with it back then & probably could have afforded to pay someone more easily then, but I was inclined & could get the job done. I am not sure about these modern vehicles though so if anyone has any thoughts on that if that is they way this thing points & I am wide open to any thoughts, ideas, & suggestions along those lines as well. Thanks again RockP2.

 

An odor in the interior, accompanied by a film on the windshield, and possibly a wet carpet by the passengers feet, are all signs of a leaky heater core. A cooling system pressure test should locate the coolant leak, however, the heater core is "neatly tucked out of the way" on this vehicle. Labor time to access the core for inspection/replacement is ~8 hours, the entire dash must be removed from the vehicle.

Lower intake manifold gasket leaks are very common on this engine, especially if the coolant is not maintained properly, (flush & fill every 36K miles or 3 years). Water pump leaks are not nearly as common, but they can develop leaks, (more rapidly when ethylene glycol is used).

Green coolant, (ethylene glycol) does very little, if anything, to protect aluminum from electrolysis. On your vehicle, the heater core, radiator core and intake manifold are aluminum. Electrolysis will eat holes in aluminum. That's why the vehicle came with Dexcool. If the coolant is not maintained properly, or the engine is not properly grounded, the process is accelerated. Mixing the coolants, (even in small amounts) causes a chemical reaction which turns the coolant to mud. Serious job to clean it out.

 

Captain Hook,
Thank you for your response. I have always tried to maintain this vehicle & the radiator fluid religiously with the mileage being about what you mentioned, but the years being longer. I have never, ever used the Green fluid in it, but have caught mechanics both a chain operation that I have had to take it to & this mechanic shop doing it & I said something about it when I caught it. They would basically respond that it really made no difference & that was just a lot of hoopla or they would basically not respond. I still believe in it. That explains why one time after I let one of the chain operations do the change & flush I observed that horrible, Black, sticky mud like stuff in the reservoir. When I said something to them about it as they were supposed to clean & flush too, but it cam back worse they claimed to clean it several times, but I eventually had to do it & it was a job & I still to this day do not think I got it done the way I wanted to & tried to get it cleaned up. Thank you. It looks to me like I will have to some how break down & get myself to replace that heater core. I once found moisture on the passenger floor, but attributed it to a clogged A/C drain. I found the drain had indeed been clogged by Mud Daubers & I unclogged it & that problem seemed to have disappeared. I guess I must have not done a good enough job. I hope this core business solved all the problems that I noted included the fuel gauge, although not sure how those two could be related. I would have thought the mechanic running that long term pressure test on the system would have located the core leak though. Do you have any thoughts on that? It is just real difficult to find a genuinely good mechanic these days that is fair. It is hard to trust those I have found here locally in this locale. I just don't know what to say & my mechanicing skills are just not what they used to be when it comes to these modern day vehicles. Do you think I could do this core myself? I used to do them on occasion easily in my older 60 & 70 model vehicles, but I don't know about this one. They cram so much in there. I am wide open to any thoughts or suggestions. Thank you for your help.

 

As for the maintenance interval, the time factor is more important than the mileage. Time is what breaks down the protective properties of Dexcool. Once they break down, damage accelerates rather rapidly. When you flush & fill, if you dilute the Dexcool 50/50 with distilled water, it offers better protection against electrolysis.

Like I mentioned earlier, to confirm or deny a core leak, without the obvious leak on the floor or film on the windshield, you really need to do a visual inspection by removing the instrument panel.... the whole thing, door to door, right down to the firewall. Then you can remove the heater case and split it apart to get at the core. After you've done a few of them on S&T series vehicles, it goes quicker, but if you haven't done one before, allow 8+ hours. No special tools, and it's not difficult, but it does require a bit of contorsionism, triple jointed shoulders, wrists and fingers, an assistant a couple of times, and a camera to take numerous pictures on disassembly

There is a thread in the "How To" section of the forum that will help.

 

Sounds like you should try to find a new mechanic.

 

first thing is to WASH the engine comparment and blow it all off with compressed air try to not get electronic's wet, they can get wet its no big deal, use the compressered air like i said then let the truck sit in a warm garage(if possable) for a day or 2.
now you have a clean and dry starting point.
pressure test the system and LEAVE the tester on for a while, now start looking for the coolant to puddle or run down the side of the engine comparment. if you do not see anything at all look at the HVAC module/heater box for ANY sign's of coolant you can even take a small drill bit and drill a small hole in the bottem of it to see if coolant comes out just remember to cover the hole with some epoxy later on!
but if you can only smell it with the blower motor on chances are its the heater core!
this is one reason why dealer's get a bad name... i'm glad the dealership i work at does things differently here in canada, we get it wrong the first time we fix it free

 

Had the smell and the wet carpet in my '95. Let me say, replacing the heater core in this thing was a.@#%&* ! The entire dashboard assy. has to come out. It took me 2 days to complete. ( I'm not as agile as I once was. ) I still love my Blazer.....Black, 2 door 4x4 LS.