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Just installed a new thermostat. No luck though. Car still overheats. I can see coolant circulating in the raradiator but the temp gauge pegs out after idling for about 5 mins. Is this a sign of something way worse....maybe engine wise??? I'm at a loss at what else to try......
Could it be that the temperature gauge is bad? Unless the cooling system was dry it almost does not seem possible to peg the temperature gauge after only idling for five minutes.Quote:
Originally Posted by Notar61
Maybe you could try a ThermoCap to get an independent verification as to what the temperature in the radiator actually is.
Attachment 5783
See: https://www.amazon.com/Mr-Gasket-247...hermocap+2470R
Dennis,
Yeah maybe it is the gauge or the sending unit. I feel like I've gone over everything else at least 2 or 3 times now.
I bought a new sending unit when I started throwing on all the other new cooling system parts. I just got it at a local parts store....looked the same as the old one. Is there something wrong with the new one maybe? Maybe its producing an incorrect reading, if it is the wrong sending unit for the car? Is that possible? Maybe I should get a sending unit from a resto-mod place....that way I know its the correct type for sure?
Guess I will try that radiator cap with the temperature gauge too.
Could the overheating be indicative of a bigger, more serious problem? My older brother seems to think the engine is on its last leg or something....but he always throws this suggestion out at the sign of any issue.
Hopefully I can get this figured out really soon. It's driving me up the walls.
thanks,
Andrew
I am just putting out ideas:Quote:
Originally Posted by Notar61
Ground the sensor while it is cool and have it connected to the gauge. The gauge should read cool. If the gauge pegs hot there is a probably problem with the sensor, or possibly the gauge.
You could test the accuracy of the sending unit by putting it in hot water. Heat the water to about 180 degrees and use a thermometer to measure it. 180 degrees should be mid-range on your cars temperature gauge. Then ground the sensor and have it connected to the gauge and drop the sensor in the hot water. The gauge should read mid-range. If it pegs hot there is a problem.
Or, just buy another temperature sending unit to replace the one you have, and see if the new sensor pegs hot the same as the previous one. If not, the problem is solved. If it reads the same, the problem is not with the sensor.
Just look at this philosphically and keep telling yourself "This is a hobby. This is a hobby." Avoid thinking about presidential politics and do not get stressed. :)
Not to be a smart *** but is the thermostat in the correct way? I only bring it up because I did put mine in backwards before and she blew her top.
Just looking for the simple stuff. Good luck.
Yeah I guess some sensor testing is in order. Hopefully I can get to the bottom of this.
And Dogshows, no worries on the thermostat question, but the old one was in the correct way and the new one I just installed went in the same way as well.
(Spring towards the engine, pointy end towards the radiator).
I may be grabbing at straws here, but is it possible my oil pump is dead or in the process of dying? I had a flickering oil pressure light lately, but just figured the oil pressure switch/sensor needed to be replaced. I read somewhere that if it was on the fritz it could cause the engine to overheat pretty quick. Just a thought, although I read that it is rare that they ever go out.
Thanks again everyone for all the help on this!
-Andrew
Andrew,
The temperature and fuel gauge both operate off a 5-volt voltage regulator on the back of the gauge cluster. Is the fuel gauge working well? If it too is misbehaving, then this regulator may need to be changed. It's a crude device at best and they will seriously alter your gauge readings if bad.
Also, there is overheating and there is high temperature gauge readings. Overheating is blowing coolant out somewhere. High temp readings can be checked for using any of the things like Dennis suggested checking for.
Of course, if the water is flowing, the thermostat has to be opening. You can often use that point, at which it opens and water begins to flow, as a "read" for what the gauge is showing. Stock gauges have no temps written on them, so if you have a 180° thermostat and you watch the gauge, when you see water just start to flow look at the needle on the gauge. If it is already pegged at that point, you can rest knowing it is not reading right. If it is reading low at that point, yet continues to climb - then you may have something totally unusual causing the overheating. These would include everything from a shot water pump, leaky head gasket, cracked block, cracked head, or the engine is on its last leg. :rolleyes: But really, as a motor gets old and sloppy, it tends to make less heat than more of it. Ring friction is at a minimum as is cam-lobe friction, which causes a lot of heat.
By now it sounds as though you have changed all the obvious things, so the question I guess I'm asking, is it a blow its lid overheating or simply an indication via temp gauge of overheating, but nothing is spewing?
Roger,
Water pump is brand new and I'm not seeing any coolant leaking into the engine oil or vice versa. Who knows on the cracked head or cracked block.
When it overheats it is a steady climb. Once it hits the high end of the temperature gauge, there is no spewing or boiling over. I've had it idling with the cap off when it pegged out and it was only really hot to the touch and maybe steaming like cup of hot coffee. That's it, nothing really explosive or overflowing.
-Andrew
So this is totally a gauge reaction? Never a spewing? While running at temperature (water is now flowing) the coolant would be exactly as you say it is. Remember, also, a radiator cap raises internal system pressure and lowers the boiling point - but can also induce pressure-induced failure, like a crack might require. These will usually lower the coolant levels pretty quickly, so if the fluid is always the same, then I would focus on the gauge. The sending units are easy to find still at many auto parts stores. No need to source these from Falcon specialties vendors and pricing.Quote:
Originally Posted by Notar61
Roger,
Yeah as far as I can tell the gauge is the only thing that is freaking me out. It pegs out pretty quick, but the car never does any spewing or boiling over.
So yeah maybe it is the sensor.
I'm going to buy an infrared temperature gun after work today, so hopefully that will allow me to verify the temperature when the gauge is pegging out. I might get a oil pressure tester kit too, just to verify what's going on with the flickering oil pressure light too.
I will report back with any new info I find out.
thanks again,
Andrew
It's definitely a possibility. My dad's 98 Contour SVT just went through a bout of the temperature gauge showing the car was overheating. But, no spewing or overflow. Turns out it was the gauge that was bad.Quote:
Originally Posted by Notar61
Kind-of a funny... but I've had about 4 different temp gauges and bits on my Ranchero so far. Had to change it initially when the sender was 1/4" pipe and I had a 1/8" pipe hole, but the 200 six ran very cool. Then I swapped to the V8 and it always "read hot", quick, but never spewed. I changed the sender (again) and the gauge changed, but still read hotter than I liked. Then I added an under-dash gauge and it seemed to read OK under normal driving, but showed hot (200°+) in any traffic driving condition. Then I finally decided to spend good money and get a more-than-$30-China-gauge (sprung for an Autometer gauge); and got a radiator cap gauge; and got a thermal pointer-meter; only to find all three read differently.
So I finally said to myself - if it doesn't blow steam, don't sweat it.
FYI: Mine is a .060 over bored 65 289, which until it is good and broke-in (if that ever happens at my current 100 miles a year) it will probably run a little warm. Many sites say don't bore a 289 to .060 over without a wall thickness check. I bought the block already bored, so I never did that. I have added as much as I can to aid cooling on this Ranchero, so I'm pretty confident that it is as cool as I can get it. If it ever blows up, I have a 302 I'll rebuild and throw into it. [thumb]