ouch, i'm overheatin bad

[m4xwellmurd3r]

So, i finally got to take my 280z out for a spin today. It ran great. till it overheated, the headgasket is fine, it doesn't burn antifreeze (no smoke) nor does it leak into the oil or anything (looked in the rad, no oil) but it overheats REALLY badly. could it be that there's some nasty garbage inside the hoses or something?

how would i know if it's the water pump, if that's the problem?

(when i say bad, i mean, within like, 5-10 minutes of driving)

[SteveJ]

First, define what you mean by overheating.

1. Was the temperature gauge reading high?

2. Was coolant coming out of the radiator?

3. Were you seeing steam coming from the engine/cooling system?

If your answer was #1, have you checked the temperature with a candy/cooking thermometer? You start with the engine cold and let it idle. You should see a good bump in the temperature when the thermostat opens.

How old are your thermostat and radiator cap? When was the last time you changed your coolant? Could your radiator be plugged? Have you tried to flush your cooling system?

[zbane]

When was the last time the thermostat was changed? If it is not opening, you would certainly overheat.

The thermostat is a pretty easy thing to check, though it is even easier to replace :stupid:

To check:

Remove the thermostat from its housing. Take it inside and place it in a pot of water. Heat the water, and as the water reaches @ 160 f you should see the center area start to open. If not, keep watching until the water nears a boil.

If the thermostat hasn't opened by this time, it is no good.

It has been suggested by others on this site that you should go ahead and spend the few extra bucks to get a genuine Nissan part, as they have a larger opening area. Makes sense to do that, so why not?

[Walter Moore]

As cheap as thermostats are, I never saw any reason to test one. If you are going to all the work to take it out of the car to test, why not just replace it and be sure?

[76Datsun280z]

Also, taking your radiator out as mentioned before and thoroughly flushing it, could be all corroted up in there causing a blockage.

[m4xwellmurd3r]

haha, no, i'm 100% sure it's over heating.

it's because the coolant is god knows how old, and has corroded/gummed up inside the lines/radiator (probably). i'm not sure about the thermostat, but the radiator cap looks farily knew, and is rated at 16lbs

i know it's not a head gasket like someone said to me today, since it doesn't burn any water, and the antifreeze is clean of oil and the oil clean of antifreeze (i did an oil change on it a couple days ago, a few things i looked for were metal chips (just in case soemthing was amiss that i didn't notice) and for any water)

i'm going to pull the hoses and clean it all out to make sure there isn't something blocking it (i've even heard taht someone had a chunk of something nasty inside it that had built up over the years)

it doesn't help that it's blazing hot in AZ

and i'm sure that the car sitting outside for years hasn't helped the coolant either. it's probably stagnant inside.

what would be the best way to flush it at home? I've heard of using vinigar and distilled water for a little while to clean it, then draining it out and putting new coolant helps, but what would your guy's advice be?

Im' also going to check the timing. It might be off since the p/o didn't check it when he got the car (he never drove it for the year he had it since he had to many ongoing projects)

I suppose i'll pick up a new thermostat tommorow when i go to the parts store.

[WingZr0]

It's been suggested you get a 180f thermostAt like me.

I just replaced my entire thermostat housing today and

boy what a fun that was

My '77 280z was doing the same thing as your Z and was Red Linning at 250f in 10 minutes flat.

When I took off the thermo housing I found there was no thermostat inside thanks to a P.O. :mad:

Anyhow I'm back flushing my Radi/coolant system in 2 days when the sealent

dries and see how she runs then.

I'll update and let you know the results :rambo:

~Z~

[m4xwellmurd3r]

ah, thanks for that info. maybe mine is shot and stuck wide open constantly.

here's another one. i'm an idiot as far as timing goes. which way advances, which way retards.

from what i understand, turning it clockwise will advance, and counter clock will retard. am i correct?

i'm also tossing a new dizzy cap tommorow. when i looked at it before, it looked like the posts inside had erroded away, and i think its' causing my engine to crossfire and miss.

I drove it tonight, it was much cooler, and it stayed about half way for about 10 minutes or so, but once i started getting on it a bit harder it heated to around 210ish.

I've found something interesting out. My car runs pretty rough, but once it hits about 3000-3500 it starts pulling harder. So i think i've got a whole mess of ignition and fuel problems, along with cooling issues hahaha.

still, i'm spending a lot less fixing this car so far, than i am trying to buy the other car, which had 0 brakes.

[WingZr0]

HA HA, at least you running on 6 cylnders

I've changed Plugs to NGK, plug wires.

Now since Ruby's been sitting, Fuel Pump, Steering Rack Bushings to MSA Polyurethanes

and now thermo housing.

She runs smooth then starts running rough at 3500 RPM's.

Valves still need adjusting and such but at least I'm doing the work I can in the mean time on my own.

Trying to buy a new head since #6 FI Port is clogged dead solid leading me to believe

theres more problems with my head than I relize so far.

Yeah, those P.O.'s messed my Ruby up :mad:

Had a look inside my Distributer, since I had to take it off to get to the thermo housing bolts, and saw there was some kind of water inside the part where the Dizzy sits into.

I'm not sure if this is supposed to be some kind of lubricating fluid but I'm doing a search function now to find out.

Anyhow I'm not sure which way or what part to Advance and Retard but I know the anwser to which direction is in the search function, I just forgot it though :cheeky: :stupid:

~Z~

[m4xwellmurd3r]

actually i'm not quite sure i'm running on all 6. i have a feeling that the crossfire from number 2 is somehow effecting number3, because number 3 acts like there's nothin goin on at all. I'm gonna see if i can rent a compression tester from checkers (i didn't see any for sale)

i'm hoping the head gasket isn't blown out to the outside of the block. I doubt it, because if i can get it to clear up and everything, and rev it to around 3k, if i pull number 3 you can hear it drop.

i might not be getting adequate fuel pressure or something.

it's a whole lot of work, and not a lot of money at this point. I really dont' want to pull the head if it's the gasket, but that's because i don't trust my abilities enough (and i'm lacking a torque wrench)

it also sucks that i don't have a garage to work in.

but it might be something like the dizzy cap causing erradic sparks, thus making number 3 act weird due to some sort of problem with the cap. who knows haha. i'll find out tommorow afternoon though. I'll also properly adjust that timing!

[WingZr0]

Sound about the right thing to do.

I got torque wrench for about 30 bucks, kinda generic though but it does the job. Make sure you have all the right suckets though in Millimeters befor you take trhe head though.

Lord knows how many times I had to go to the parts store to another socket for the right size of bolt :rambo:

Pretty much I'm making my troll set as go :cheeky:

I'm tossing my Head in the garbage though and going with an HKS Steel racing headgasket from MSA I hope. Because the rubber head gasket on there now is starting to leak in areas it didn't before, problely from the over heating.

As long as the head, which is fixable, hasn't warpped.

Still have to replace my Dizzy and Cap but it sounds like thats the only thing you have to do to get back on track

If you have to pull head after that for some reason make sure you have ALL the tools for the job though or else you'll be at NAPA Auto more times than a Starbucks lunch break

[m4xwellmurd3r]

actually, i highly doubt that.

I work at starbucks, some i'm there 6/7 days a week ^^

I've got a metric socket set from like, 4mm (or less?) all the way up to 19mm (go craftsman) I've also got a metric wrench set from like 2mm all the way up to like 21mm

i don't know if this is possible, but could carbon traces in the dizzy cap cause odd sparking, causing one cylinder to act dead?

i don't think it's the head gasket, but i'll make sure EVERYTHING is taken care of before i decided to go in and pull off the head.

what does a gasket leak sound like?

(random, but something i found out that made me smile a bit. last month of the 78 was 6/78, my car, 5/78 i think it's within the last 10k cars (vin 46x,xxx, last vin, 470,009)