Okay. So everyone knows I had a heater hose blow on me yesterday. I'd like to throw out some general info and see if we can figure out why and what long term damage might have been caused...

The background:

Temp gauge has been acting funny for some time now (maybe 1-2 months). Would rise well above normal, sometimes peg out at full hot. Obviously, if everything else is working as it should, the engine would either boil over into the overflow at this point or pop the radiator cap, right? Wrong. Why? The first few times this would happen (and at random after that), I would pull over immediately and check for boiling coolant. Overflow was perfectly normal. There was also never any signs of leakage (ie; I never smelled or saw any coolant anywhere :shrug

The heater would work at random. It wasn't related to engine speed or temperature. I could hold the lower gears longer in an effort to maybe turn the water pump at a higher speed and there was no change. Also, when the gauge would be way up there (maybe a dozen times or so in this entire period), I would crank the heater full blast and hit the windows. At these times, there was never any heat. :shrug

Now, last night, I replaced both the hoses to the heater core and purchased a new thermostat. In driving the car afterwards, I realized I had forgotten (due to extreme lower back distress and overall disgust) to change it. Temps have remained perfectly normal. I refilled with fresh coolant and have a jug of water in the back just in case now. If the thermostat was shot, wouldn't it revert back to the funky temp readings?


The hose that broke was the one closest to the head. You know the pipes that come around by the battery side? It was the inside one. It blew at the pipe and not the middle or the firewall. Could there have been something inline in that hose that blocked it and finally the pressure became great enough to pop it?

If the heater and engine temps had been acting normally this past couple months, I wouldn't be so concerned, but considering something was keeping the temps up and the heater cool, I'm not 100% sure that changing a couple hoses necessarily solved the underlying problem.

Finally, should I be concerned about any long term damage? The MLS will be replaced, as will the head in a couple weeks. What should I be keeping an eye out for? Please discuss.

Thanks!

The wierd fluctuations you've been having do sound like the thermostat, which can act irregular as it so desires. You have to have a pretty serverly blown head gasket for that to fluctuate your coolant heat (more so than the typical oil leak at the rear driverside bolt on the head).

Heh, every person I know locally w/ a 2GNT has had their heater hoses go on them before. In my case the hose didn't burst, it just started leaking where those cheasy little double ring clamp deals clam it to the water pipe off of the head. So I clipped the end of that hose scooted it up some (the hose looked good other than the very end and there was plenty of slack) then used a normal screw type band to tighten it.

don't have any answers but hell, this is a discussion so here's what i've seen.... i have a radiator leak and have noticed if i let the coolant get a little low my temp guage would do as you described, rise to the hot range then cool off real quick, much too drastic of a change to be representing the actual engine temp. my guess is that the coolant wasn't flowing over the temp sensor but steam instead, showing the high temps. (don't think the engine was actually overheating). these false heat readings and lack of coolant may explain the heater not blowing hot air. correct me if this is obviously wrong. sounds like you were keeping an eye on coolant level so that's probly not it. And as for the small heater hose on the front, i've had that blow out twice now and replaced the hoses to the firewall as well. this has all happened over like the last two years and don't think it's any kind of chronic problem like a clog in the system, guess the hoses just like to give up in our cars. i don't think you need to worry about damage unless you really overheated the engine but as you said it should have been belching steam at that point, so i'd just keep an eye on the coolant level and temp guage for a while and see what happens. good luck

edit: oops.

Brian,
Normally when your thermostat goes, you will notice that the coolant will actually lower instead of rise. In the morning you would notice that it would take quite a bit longer then usual to warm up. Basically because the thermostat is always letting coolant into the engine.

Now, since you live in AZ. The coolant wont stay in the rad. long enough to cool down. So that would explain why your temps would rise.

Hope this helps.

Nick
97RS

turbo8u> shut your SUCK
ZAO684: NIPPLE warning...maybe>?
turbo8u> yea i was a window licker on the short bus in junior high

Originally posted by Collente
Brian, Normally when your thermostat goes, you will notice that the coolant will actually lower instead of rise. In the morning you would notice that it would take quite a bit longer then usual to warm up. Basically because the thermostat is always letting coolant into the engine. Now, since you live in AZ. The coolant wont stay in the rad. long enough to cool down. So that would explain why your temps would rise. Hope this helps. Nick 97RS turbo8u> shut your SUCK ZAO684: NIPPLE warning...maybe>? turbo8u> yea i was a window licker on the short bus in junior high

Not necessarily. You have to be specific when saying "the thermostat goes" because if it fails in that it is stuck closed, the coolant will never reach the radiator causing overheating. If it is stuck open then you are correct in that it will take your engine longer to warm up as immediately your coolant is sent through the radiator and back to the block. However if the thermostat fails in the stuck open position it has no effect on the length of time the coolant is in the radiator. That is based on restrictions in the coolant passages and hoses, and efficiency of the water pump.

Originally posted by Blk95GS
my temp guage would do as you described, rise to the hot range then cool off real quick, much too drastic of a change to be representing the actual engine temp.

That's exactly what was happening! It would peg out hot and then drop all the way back to normal in about 10 seconds. Then climb back up there.

Originally posted by Blk95GS
my guess is that the coolant wasn't flowing over the temp sensor but steam instead, showing the high temps. (don't think the engine was actually overheating). these false heat readings and lack of coolant may explain the heater not blowing hot air.

Do0d. That makes perfect sense to me. Werd to you! I agree that the hoses are cheesy. Some of them get slimy on the outside and I'm starting to think that it had just gotten hot enough to produce enough steam to pop the weakest link of hose.

So I guess I'm more or less safe then. I just wanted to be sure.

Thanks everyone!