Dancing Temp gauge... BHG?

[spamalope]

Ok, well I just got back from limping my '85 MKII 175 miles with all kinda of funny temo issues. I was driving rather quikly up some steep mountain twisties and I noticed that the temp guage was a hair under the red. So I pulled over checked out the coolant level and the overflow was empty. So I let it cool and take it to the next town and fill the reservoir and the rad itself takes about 1/4 of your standard jug og coolant. Now the car was just in at a shop a few days ago and they had just but on a new Rad cap (the old one held 0 lbs.) but said nothing about low coolent, so Im assuming it was good. So I end up limping it home the whole time the temp gauge would hop from middle to red very quickly, like seconds. any grades or anytime I'd give it alot of steady gas it would jump up to red. Also, I;ve had an old leak that pools some oil in the Plug/camtower Valley, I've now noticed that after these hot runs, when I pulled over to let it cool I saw the oil was bubbleing, like air bubble from under the little oil pool around the head bolts. I've also noticed a little but of blackish/grey stuff floating in the overflow bottle.

So Im thinking BHG but the headgasket was redond by a shop along with a fully rebuilt leveled head at 122K (169k now). Also there is no real loss of power, just the dancing gauge. I also can't find where the coolent is going with no steam in the exaust. Could the new Rad Cap screw anything up like work some junk loose? I;m assuming a BHG but I'm not set to fix it at the moment. Thanks, Frank

[Donn29]

Comperssion test?
Sounds like air bubbles. I thought I had a barly blown HG but turned out farther down the road that my heater core was leaking. Try temp. bypassing it.

[BillyM]

Bubbles comin up outa the head bolts?

...no good.

Do a compression test on the cooling system, make sure it will hold 15psi, then start the car and stab the throttle to the floor a few times and see if it pushes the pressure up.

--billyM

[BuddyJ]

You're gonna have to investigate that. My car did similar things, leading me to replace the temp sensor. Didn't change much.

In my case, I think it's a short in the dash. If I slap the right hand side of the gauge cluster, it fixes it and the temp gauge goes back down to where it should be.

[spamalope]

Hmmm, just drove the car 35 miles to work without a single switch from the gauge, and a normal driving car. I did have to put some water in her this morning though... I'll see if I can dig up my compression tester.

[Donn29]

sounds like bubbles to me, sounds just like my situation. Try bypassing the Heater core, if it has compression and what billy said.

[spamalope]

Well, just got it back from a Coolent Chem test and...

Fcuk me... a BHG!

Anyone want to buy an '85 SDR Auto with a BHG shoot me a pm... sigh

[CarFreek]

Ok, well I just got back from limping my '85 MKII 175 miles with all kinda of funny temo issues. I was driving rather quikly up some steep mountain twisties and I noticed that the temp guage was a hair under the red. So I pulled over checked out the coolant level and the overflow was empty. So I let it cool and take it to the next town and fill the reservoir and the rad itself takes about 1/4 of your standard jug og coolant. Now the car was just in at a shop a few days ago and they had just but on a new Rad cap (the old one held 0 lbs.) but said nothing about low coolent, so Im assuming it was good. So I end up limping it home the whole time the temp gauge would hop from middle to red very quickly, like seconds. any grades or anytime I'd give it alot of steady gas it would jump up to red. Also, I;ve had an old leak that pools some oil in the Plug/camtower Valley, I've now noticed that after these hot runs, when I pulled over to let it cool I saw the oil was bubbleing, like air bubble from under the little oil pool around the head bolts. I've also noticed a little but of blackish/grey stuff floating in the overflow bottle.

So Im thinking BHG but the headgasket was redond by a shop along with a fully rebuilt leveled head at 122K (169k now). Also there is no real loss of power, just the dancing gauge. I also can't find where the coolent is going with no steam in the exaust. Could the new Rad Cap screw anything up like work some junk loose? I;m assuming a BHG but I'm not set to fix it at the moment. Thanks, Frank

Any warranty on Shops work?-They may have torqued to Toyota spec instead of what these engines need-70+ lbs

[spamalope]

lol, the last owner had the work done and it was done in like 1997 so I doubt it. I'm sure they would laugh in my face...

Might be time to save $ and do a 1uz swap

[Angkistrodon]

I feel you for the BHG. I caught up with this thread a little late. My temp guage will sometimes shoot to the red, but a few taps on the dash and it will quickly lower to where it needs to be.....guess it needs a little lube.....