I just got back from a 5 mile trip to the auto parts store. On the way back, my temp spiked from 180 to almost 250! I pulled over and shut it off. There was no steam or anything. There was coolant in the overflow still. Everything seemed normal. I started it up and drove home. On the way it spiked a couple of times then quickly went back to normal again. I was thinking there might be bubbles but I had flushed the system a while back and drove many miles since with no problems. I replaced the thermostat (180), hoses, and radiator a little over 6 months ago. I don't get it. Both my Scanmaster and my temp gauge read the same and I assume they aren't on the same sending unit. I don't know.
Bad Thermostat?
- Thread starter DaveyX87
- Start date
When steam hits the sender you should see a false reading of around 212F. If you were really at 250K you should have seen bubbles burping into the overflow. Not to mention when engines get that hot they have a 'smell' to them.
When you installed the thermostat, did you drill a steam hole at 12:00?
And you're right, they are two different senders, but they're mounted very close to each other.
When you installed the thermostat, did you drill a steam hole at 12:00?
And you're right, they are two different senders, but they're mounted very close to each other.
dirtymax731
Member
- Joined
- Mar 24, 2013
You can test them by having it in water and heating it up to see if it pops.
I'm gonna pull it and try that. I wouldn't think it would be bad since it's 6 months old. The heater isn't working either so I know somethings wrong. I just hope it isn't the water pump. Everything else is new (hoses, heater hard lines, heater control valve, Alradco radiator).
- Joined
- Feb 18, 2006
Overheating? No heat inside? Your coolant is low. Now the magic question. Where'd it go?
The fan is working but the coolant was a little low. I topped it off and made sure there were no bubbles. It seems like there is very little pressure in the heater hoses while running at temp leading my to believe that the stat isn't completely opening or there is a clog somewhere, or a bad water pump. There doesn't appear to be any water in the oil, leaking heater core, or water pump. We will see when I pull the stat.
- Joined
- Feb 18, 2006
The radiator cap is what holds pressure in the system not the thermostat.
NY Twin Turbo
All the good stuff.....Times 2.
- Joined
- Dec 10, 2014
Strange. It seems as if you have air in the system. But where did the coolant go? Maybe not in the oil but what about the combustion chamber? No steam from the tail pipes? What about combustion blowing into the coolant passages through a head gasket?
- Joined
- Feb 18, 2006
You won't always see it in the oil when the leak is small. It will coagulate on the valve covers and intake. "White pillow'e slugde".
This can be early signs of a head gasket problem. If it overheats again and coolant disappears out of no where, it's a done deal.
This can be early signs of a head gasket problem. If it overheats again and coolant disappears out of no where, it's a done deal.
NY Twin Turbo
All the good stuff.....Times 2.
- Joined
- Dec 10, 2014
I would think it's already a done deal.......No?
If my motor made it all the way up to 250 degrees, I would pull it out the next day. I would have to break it down and see what happened and if anything was toast. I'm nuts that way. I wouldn't be able to sleep without knowing if it was compromised in some way.
I had a similar thing happen to me except it was the Northstar engine in my Cadillac. Minus 30 in February I drove about 2 kilometres and the engine management system put it into limp mode then promptly shut it down as the temp reached the "red" zone. I drove it the day before without issue and now it took 2 jugs of Dexcool to refill it. Where did it go? It remains a mystery as it has operated without reoccurrence since. My point to all this is I would be tearing anything apart before putting some more miles on it.
NY Twin Turbo
All the good stuff.....Times 2.
- Joined
- Dec 10, 2014
Certainly. I would definitely want to verify the readings were correct. I believe he stated both his gauge and Scanmaster agreed with one another from 2 different sensors.
I really think it was a false reading. I hope so. Come to think about it, I lost a little coolant when I had one of the heater hoses off temporarily. On another note, this happened right after I blocked off the EGR. I'm not sure if that effected it somehow. Now I can't sleep. The exhaust has always seemed a little steamy at times. I assumed it is running rich as my BL is a little high (142). I've been chasing what I thought was a vacuum/exhaust leak. I fixed all the leaks but it still idles a little rough and stumbles sometimes. Maybe it has been a head gasket all along.
I went out to the garage this morning and opened the radiator cap. It was pressurized and I haven't driven it since I topped it off and gor all the bubbles out. The water was low again. I inspected around the water pump and it felt wet. The garage rug was wet. There was some water on the pax side intercooler bracket. It doesn't appear the hoses are leaking, plus they are new. I'm thinking it's the water pump.
