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Old 11-27-2013, 01:33 PM   #1
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Angry WHERE is the Coolant going and WHY engine overheated?

On my 'new' 1992 Miata, which has less than 28k on a new engine (replaced everything- transmission, clutch, brakes, etc. with Performance/Racing parts, I had a once in a couple hundred miles 'squeel' in one of the belts. Car ran great, temp guage ran only a third up, oil pressure was near 60#, no overheating (even hot days in stop/go traffic with a/c on the temp guage never rose up from normal position. The front belt (a/c and PS) was nearly new... back belt for water pump/alternator showed age and had some cracks showing; and since the 'When' for the timing belt was unknown, I decided to do some preventative maintenance.

A local garage with a good rep supposedly replaced the timing belt, both front belts, installed a new water pump, new head gasket, and installed a new set of iridium plugs. I won't boor everyone with the 8am to 6pm day for this work other than the mechanic wasn't familiar with this work and had to ask questions from the owner repeatedly AND was having 'family issues', taking 50-60 phone calls and spending 70% of his time WHILE working on the car talking on the phone AND still 'doing' the work. ( I held a light repeatedly so he could see properly and I stayed the entire day over worry about the way things were going).

Drove 14 miles home that Friday with no issues and put a section of cardboard under the Miata when I arrived home to watch for oil/water leaks. Didn't go anywhere over the weekend. On Monday morning I checked oil level and checked water in expansion tank (both normal) and nothing showed on cardboard. Thought I was OK and headed out-driving to another town for a doctors appointment and to see my ailing mother. I got about 5-miles when temp guage rose to just above mid point- stopped and checked engine, finding no signs of overheating (no steam, nothing dripping onto the ground, and no heat etc. radiating off the engine) and there was still 1/3rd water in overflow tank but I added 20oz cold water to be sure as worst that could happen was it'd go onto the ground. Drove another 5 miles and when I came to a stop the temp guage pegged or flopped in one motion all the way over to the stops on the hot end. I stopped and turned off the car , inspected engine and found no signs of heating up (again there was no steam, nothing dripping onto the ground, and no heat etc. radiating off the engine); and I still had water in overflow tank but added TWO 20oz bottles of cold water for insurance this time. I drove another 2-3 miles when I noticed the oil pressure was dropping to just under 40# yet the car was running OK until just before I reached the garage where the maintenance work had been done when the car began running rough, engine exhaust sounded funny and some smoke was coming out of the exhaust as I pulled into the garage driveway and I shut off the engine when I was well into their driveway. The engine began to smoke as I raised the hood. It WAS NOW hot. NO water in overflow tank. In less than 30 minutes the owner took a five gallon watering can and poured 1/2gal or more into radiator (he did squeeze upper hose first and said it was okay before he removed the radiator cap). A column of steam immediately burst from the radiator and continued for a couple of minutes. He again poured at least another half gallon into the radiator and the same column of steam erupted from the radiator. I was talking to my best friend who's a mechanic and he yelled the dumb _ _ _ _ would crack the block which I repeated to the garage owner, and when owner said he hadn't put in enough water, I handed the phone to owner (garage) to have my friend explain it to him. Two hours later the car would not start or come close to turning over.

It would appear the engine is somewhat ruined. What's known for sure is the head gasket is blown. Now it's been day and half and the garage won't return my calls. I am going there now to see what the garage owner's 'STORY' is.

My question for the group. WHAT COULD HE HAVE DONE TO CREATE THE OVERHEATING PROBLEM where none had existed before? WHERE WAS THE WATER GOING? Could his putting on the wrong water pump have caused the problem? (Had problems with the wrong parts being delivered twice. Didn't get the Gates timing belt and other belts requested. I was supposed to get all the parts (nothing really wrong with them) and didn't get either the timing belt or the water pump. A lot to ask and hard to guess at but I would like to hear from someone knowledgeable who might have some input on what I'm dealing with. Thanks. davzway
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Old 11-27-2013, 02:05 PM   #2
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Lots of things could go wrong. Slipping/broken water pump belt, stuck thermostat, failed water pump, clogged radiator, cooling fans inoperative (though a car in motion doesn't care as much about fans).

Why was the head gasket replaced for general maintenance on a 28k motor? Did you mean cam cover gasket? If it is the head gasket, I suppose there could have been some obstruction to the coolant passages caused by using the wrong head gasket/improperly installed gasket, but I don't think it would have taken over 20 miles for a problem that significant to show up.

EDIT: Hindsight is always 20/20, but never continue to drive a car that is showing temp spikes.
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Old 11-27-2013, 02:26 PM   #3
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Sure they put any water into the engine/radiator at all after doing the TB job?
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Old 11-27-2013, 03:28 PM   #4
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First thing...

The Miata engine is notorious for holding air in the head. The air burp/purge process goes as follows:
  1. Seal up engine
  2. Jack up the front of the car as high as you can get it
  3. Add coolant
  4. Start engine with nose elevated, cap off
  5. Let it idle up until the thermostat opens
  6. Once thermostat opens and air belches out, add coolant

If you fail to do this, you don't fill the motor with coolant and you are fucked.

Another thing...

This is a factory thermostat:


This is a shitty generic thermostat:


Notice something missing other than the second valve? The factory thermostat at the top has that weird brass tab thing sticking out of a tiny hole between the two thermostat valves that allows air to bypass the thermostat to help purge the block. The thermostat pictured above without this provision is fail.


This one has a small hole with a brass jiggler tab on the right front edge of the thermostat, just like the factory one even though it only has 1 valve. This is OK but it MUST be oriented in the 12 O'clock position when the thermostat is installed to get as much air out as possibe. Some people will even drill a 1/16" hole in the thermostat to accomplish this. My experience shows the bottom line is that you damn near must use a thermostat with a provision to burp/purge air on the Miata.

If you DO NOT install the correct thermostat and you DO NOT burp the air out of the system, YOU WILL BE FUCKED. I bet you a dollar your "mechanic" cheaped out on the thermostat AND didn't burp the system.

Quote:
Originally Posted by sharkythesharkdogg View Post
Why was the head gasket replaced for general maintenance on a 28k motor?
+1, WTF?

Quote:
Originally Posted by Leafy View Post
Sure they put any water into the engine/radiator at all after doing the TB job?
Bingo.

I'm betting that your coolant didn't go anywhere because there was never any there to begin with.
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WHERE is the Coolant going and WHY engine overheated?-61af1e11b73f0ffa24470ecc8cde60e3__44015_zoom.jpg   WHERE is the Coolant going and WHY engine overheated?-thermostat.jpg   WHERE is the Coolant going and WHY engine overheated?-143-0687_7073.jpg  
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Old 11-27-2013, 04:00 PM   #5
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Oops, I misspoke as it was the Cam cover that was removed. I did stop and turn off the car when temp guage flopped over. No sign of overheating, no steam, nothing going on the ground.. nothing. Started up and continued on the way to the garage. It was only the last 0.6 miles that the oil pressure guage started to drop, and by that time I finished the last block into the garage driveway.

Until they worked on the car,, a friend drove it for 4k and I drove it for 1k and NO issues, no overheating, nothing. It was 'preventative' maintenance to replace the once in awhile squeaking in the back alternator/water pump belt that did have some surface cracks under a bright light. At that point, timing belt and NEW water pump, etc. was all preventative stuff while in there for the rear wp/alt belt. Anyone who would use an old alternator/wp belt might have used an old timing best. I was worried due to the WAY the current work was done as I described in the original thread subject; as the man doing it was not an experienced mechanic (his normal work was rebuilding transmissions). They currently say they are having the head magnaflux and resurfaced with new gasket set on everything. I have real concerns for the motor after his pouring in cold water into the really hot radiator (twice with tall column of steam last several minutes) but now cannot say anything until it's back together and they SAY it is done. The Miata had better still have 60# oil pressure and pass a compression check at the very least; then will watch for signs of using oil (no oil usage in 3k miles between oil changes). Right now, it is wait and see. Miataless for a week minimum. A not very happy ... davzway

Last edited by davzway; 11-30-2013 at 11:54 AM. Reason: Language to be understandable
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Old 11-27-2013, 04:08 PM   #6
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Quote:
Originally Posted by EO2K View Post
First thing...

The Miata engine is notorious for holding air in the head. The air burp/purge process goes as follows:
  1. Seal up engine
  2. Jack up the front of the car as high as you can get it
  3. Add coolant
  4. Start engine with nose elevated, cap off
  5. Let it idle up until the thermostat opens
  6. Once thermostat opens and air belches out, add coolant

If you fail to do this, you don't fill the motor with coolant and you are fucked.

Another thing...

This is a factory thermostat:


This is a shitty generic thermostat:


Notice something missing other than the second valve? The factory thermostat at the top has that weird brass tab thing sticking out of a tiny hole between the two thermostat valves that allows air to bypass the thermostat to help purge the block. The thermostat pictured above without this provision is fail.


This one has a small hole with a brass jiggler tab on the right front edge of the thermostat, just like the factory one even though it only has 1 valve. This is OK but it MUST be oriented in the 12 O'clock position when the thermostat is installed to get as much air out as possibe. Some people will even drill a 1/16" hole in the thermostat to accomplish this. My experience shows the bottom line is that you damn near must use a thermostat with a provision to burp/purge air on the Miata.

If you DO NOT install the correct thermostat and you DO NOT burp the air out of the system, YOU WILL BE FUCKED. I bet you a dollar your "mechanic" cheaped out on the thermostat AND didn't burp the system.



+1, WTF?



Bingo.

I'm betting that your coolant didn't go anywhere because there was never any there to begin with.
I KNOW they didn't have the car at any angle and never did anything to purge air. They didn't replace the thermostat (I asked and he wasn't sure where it was), but am fairly sure it wasn't replaced. If it had a good thermostat (i.e. it worked before they worked on the car) it HAS to be something in their installation that caused a problem. I did see him pour some coolant in and some water; however cannot say how much. The mechanic stopping to answer the phone every 15 minutes was making ME nuts as well as his talking on the phone while reinstalling the parts. There were TWO wrong parts delivered (who's fault I have no idea) during this process. Never did get the Gates belts quoted for and then wrong tension/idle pulley /spring was delivered, etc. Military has a term for this, when things go from FUBAR to a real ClusterF_ _ _ .
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Old 11-27-2013, 04:14 PM   #7
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OH, and a BIG THANKS PARD.. THE INFO IS APPRECIATED. I have copied the text (pic didn't) and sent it to myself in email to print out and give to the garage. Maybe get right the second time IF the engine isn't toast. davzway
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Old 11-27-2013, 04:27 PM   #8
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No worries man, I hope these muppets get you straightened out.

Something else I do while purging is it "pump" the lower radiator hose by squeezing it (provided its not one of the ones with a steel coil in it) to motivate air bubbles out of the head/block.

The other option if elevation cannot be achieved is something we like to call "Lisle Magic Funnel" (not to be confused with the Hustler Funnel Mask)

Lisle 24610 Spill-Free Funnel : Amazon.com : Automotive Lisle 24610 Spill-Free Funnel : Amazon.com : Automotive



Read more about the air purge issues and tricks here: https://www.miataturbo.net/engine-pe...n-68587/page2/
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WHERE is the Coolant going and WHY engine overheated?-410gky372tl._sx300_.jpg   WHERE is the Coolant going and WHY engine overheated?-410gky372tl._sx300_.jpg  
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