over heating 84 carrera

[rob6]

hi guys, my carrera is running hot on the highway( 10 oclock tick).Im fighting this problem for a while. Ive looked thru the vacuum lines on the emission systems and cant find any leaks, that are obvious. I know its a lean burn condition or something Im missing. The car set for a while(6 mos) I set the valves, changed oil, replaced some cracked vacuum lines. The car seems happy for about 10 miles than slowly creeps up to a high temp, it also seems a bit down on power. I did a compression check and all cylinders are 140 psi at 5000 feet. Is there a thermostat im missing somewhere? are there any vacuum lines that are tough to find? It has run cool for many years, and now this problem has cropped up and leaving me a bit frustrated.---thanks

[DonMo]

Put your hand on the oil cooler in the front passenger wheel well. If it isn't hot to the touch. Your thermostat isn't opening. You are running too hot, it isn't timing that is causing temperature like that. You aren't getting air to the oil.

[rob6]

Thanks you are correct I just went outside and the oil cooler on that side is cool to the touch ---where is it and how do I change it? ---- you guys are awesome

[tonythetarga]

The regulator that sends oil to the front cooler is located in the right rear fender well just in front of the wheel. That is where you want to make sure there is a temperature differential. There is another thermostat on the engine near the firewall but if your oil pipes are warm on the oil tank side of the wheel well and are cool upstream as they would be on the way to the cooler, then that regulator is likely the problem.

[rob6]

let me get this straight --- a regulator , or heat controlled valve, that resides under the wheel well in the oil line, is it obvious? there is also another heat controlled valve in the oil line near the firewall. the line returning from the front oil radiator is cool , so the problem is the valve in the oil line under the wheel line --- which part is that in the catalogue?

[ael911]

do a search on this forum under thermostats, there are a ton of information on replacement and repair of auxillary thermostats and the engine mounted thermostat.

[rob6]

I see it now, does the entire housing need to be replaced? or is the regulator inside the housing

[ael911]

you can just replace the plunger that goes inside the side of the thermostat. Vertex sells the plunger insert for about $50 bucks. The the tough part is the removal of the cap. There is no known tool that fits the slot so most of us had to use lots of PB blaster and chewed up the cap with a pair of large channel locks. Before you spend money, check to make sure the external thermostat is indeed the problem. With the engine warmed up, the lines to your oil cooler at the front of the car should be hot and extremely hot. If not, check the lines behind the external t-stat that run back to the engine. If those are hotter than hell, chances are your problem lies in the external thermostat. If those lines are not hot, hold your hand close to the engine oil cooler (silver aluminum box with mesh fins on the bottom right side of the engine) with the engine running. The engine cooler should be extremely hot. If the engine cooler is not hot, your problem is the engine mounted thermostat. That part is harder to replace without at least a partial engine drop as it is mounted on top of the engine where access is extremely tight. That thermostat is a complete replacement unit and our host sells them for about $80. Hope this helps you out.

[ael911]

A bit of correction on my last post, even if the engine mounted t-stat is bad, the lines that go to the external t-stat would still be extremely hot according to Chuck Moreland at Elephant Racing. The two systems are independent of each other.

[rob6]

thanks guys I also searched the forum for advice. I think ill try tapping it and see if that helps, as I saw in one post, if not Ill try the replacement, Im pretty sure its the external thermostat, as the lines were cool after running a while but Ill run it again manana and check again for the internal themostat Ill report back as I go......

[rob6]

http://www.pelicanparts.com/catalog/shopcart/911M/POR_911M_ENGoil_pg3.htm#item11

sealing ring and side piston, right?

[ael911]

Yup, those are the parts. You might consider getting a spare cap also since the one you take off might get chewed up.

[rob6]

do I need to hone the cylinder?

[ael911]

Not quite sure what you mean by that? The plunger is a straight drop in part. There is a wax insert inside the plunger that expands when the oil temperature reaches 190 degrees. Over time, the wax either leaks out or the plunger sometimes gets stuck. Try whacking it with a rubber mallet or ball peene hammer. This didn't work for me as I had to replace the plunger

[rob6]

thanks I was envisioning a plunger with a sealing surface much like a brake cylinder, intersesting waxy substance eh, wonder what its composition is

[rob6]

ok I rapped on the regulator today and the car is running about in the 8:30 position around town, not quite half way up the gauge, is this cool enough for around town on a 90 degree day?, the front oil cooler seems to be getting warm now but Im not sure the regulator is opening all the way, maybe I should replace the piston anyway. I kind of remember it ran cooler last year. however, it is clearly cooler than it was before I rapped on the regulator with a hammer---any thoughts?

[tonythetarga]

with normal driving and not a lot of stopped (waiting) time while running, anything under 9 o'clock on the gauge is pretty normal. Personally, I would monitor the temps for now. If you find it sticks again, then I would replace the spring and plunger and take away the worry of whether it will open or not.

[nesslar]

....gotta love a car you can fix with a hammer....

[DonMo]

Run till failure. The job is not fun and you really need to know whether you are doing the internal thermostat or the external. Plus, you may get lucky and it was just a piece of grime on the piston and it won't come back.