umhb_dad

i have read through as many posts as i could find - still can't get this fixed. Thanks for the help.

My daughters 1999 EX SOHC overheated three days ago; radiator was split open

-changed the radiator, new cap, rad hoses, refilled with new coolant 50:50
-fan would not come on - test wired fan direct to battery - ran good
-swapped relays between a/c fan and radiator fan; fan would not come on
-jumpered the thermoswitch connector - fan came on
-checked then changed the thermoswitch and thermostat
-fan comes on when hot, but seems to shut off too soon
-attempted to purge air from the system

It now may take 20min to an hour or so for the car to overheat - temp gauge is stable at 1/2 way when driving, then may start climbing quickly at a stop light
I did not see any white smoke, water in the oil, or exhaust residue or bubbles in the radiator. Both radiator hoses get hot
i changed the water pump and timing belt three months ago.

I may not have got the jiggle pin of the thermostat at the top position - how critical is this for getting the air purged?
Is there more than one thermoswitch on this car?
Is there a radiator fan timer?
I saw that the computer is hooked into the fan relay - is it typical for this computer to cause trouble?

many thanks for the help

09chaplak

Did you go through the FAQ's on the cooling systems and how to properly bleed the system?
https://honda-tech.com/forums/honda-civic-del-sol-1992-2000-1/faqs-frequently-asked-tech-questions-1998336/ down in the cooling system section.

tony_2018

Dad needs to learn to read the FAQs.

umhb_dad

i looked at that - thanks
any ideas on the questions in the post?

eghatch9295

iTrader: (1)

all no to your questions.

tony_2018

Did bleed the system properly? Was there a reason why the water pump and timing belt was replace 3 months ago? The ecu does not turn on the fan, the fan switch is on the thermostat housing and that is what triggers the relay to power the fan.

stupidhard

um the jiggle pin clocking is important. bubbles rise and the pin is supposed to be clocked at 12. if everything else checks good... that should be your sign.

thanks dad (is what she will say)

-chris

94CivicHatchGSR

iTrader: (1)

Lol..

I actually had a similar issue overheating. Replaced rad cap, thermostat (with pointed up at 12 o clock...it only went in that one way), fan switch, relay, all fuses good... Didn't overheat anymore in traffic for 3 weeks, today it started again. It may be air in system...

tony_2018

I've never had to do this but people tell me to raise the frontend of the car higher than the engine and that should help air get to the radiator to escape.

umhb_dad

i thought i bled it correctly - have to try again (design is a bit odd for me, with the upper radiator house being the inlet to the engine)
water pump and timing belt changed just for regular maintenance
thanks for the help

umhb_dad

i missed it on the jiggle pin - on this one the gasket had two locating tabs, but the thermostat could clock to any position

umhb_dad

turns out it was the head gasket - continuous stream of bubbles in the radiator overflow while the car was hot. now i've got some work to do...

TomCat39

That's not overly surprising being it overheated once. If it gets hot enough the head almost always warps and the head gasket will not seal after that.

Now the head has to go to the machine shop to be milled for levelness and you also have to use a precision straight edge and check the block for warped condition. Once you know they both are truly flat and smooth, your new head gasket should work like a charm.

umhb_dad

thanks - got the head off - couldn't find my feeler gauges, but head has a noticeable warp. apart from checking for cracks and valve problems, do you know if the camshaft races give trouble when the head warps, or just a re-surface for the head and it's good to go?

tony_2018

Check the surface of the block for warpage as well before taking the head to the shop, if both are warped just look for another known good engine.

TomCat39

The machine shop can tell you if the head is salvageable. If it's warped beyond a max amount you can't save the head.

And like tony mentioned, you need to check the block too. Which of course requires your feeler gauges and the precision straight edge.

If the block is warped too, no use trying to save the block or the head.

umhb_dad

Machine shop said the head was warped and two valves not holding pressure, but no cracks - re-built the head ($225). Found the feeler gauges - block is flat to 0.003"

Going back together well, except one of the head bolts squeaked and popped as it was torquing up - very difficult to tell if it got to the correct torque. Head bolts are new, and i did oil them as the shop-manual said and blew out the holes but did not chase them. Is it too late to pull just the one bolt and chase that hole without wasting a head gasket?

Also camshaft sprocket now looks to be about a bit off, maybe 1/8 of a tooth from the marker. I guess this is due to the change in the head height - how much is too much before i need to get an adjustable sprocket?

thanks very much for the advice

TomCat39

Nope, it's not too late.

If you've seen an ARP catalog, they get into the science behind lubrication and torquing fasteners. It's been shown that with standard oil, you actually have to loosen and retorque the fastener several times before the the torque is accurate.

I don't have my catalog with me so I can look up how many times but if anything, since you are not using their specially formulated lube and just using oil, I would actually loosen all the bolts, chase them all, then torque/loosen/retorque them all at least 3 times to the first step torque rating. Then proceed to go to the final torque rating.

Of note, do ALL of this in the proper sequence for both loosening and torquing.

This might be overkill but I tend to be an overkill kind of guy.

Hopefully someone else can pipe up about the cam gear from the milled head.

umhb_dad

thanks - i follow what you're saying - my hesitancy with pulling the bolts goes back to my chevy small block days - the fire rings were one shot deals; once squashed, they never held pressure properly again if they were released. can these honda head gaskets be re-used?

umhb_dad

Running good so far - no problems (no bubbles in the radiator overflow). very smooth.

I tried a technique that i read about for aircraft bolts; i backed the bolts off to 36ftlbs, then estimated the amount of swing of my wrench handle to bring them all back to 49ftlbs (about 1/8 of a turn). then i did the same for the bolt that was popping.

I had read that this is a preferable technique for consistent bolt load - by torquing to a low value, then turning the bolt by a fixed amount to the final set point. Then the final bolt load is only a function of the thread pitch and the fraction of turn of the bolt, and not by the friction under the bolt head or friction in the thread itself (unless of course it's a low grade bolt and it twists, which is another part of the problem)

thanks again for all the help - hope it holds together for at least a few more years!

tony_2018

Gj day! And no I wouldn't recommend reusing head gasket.

TomCat39

No the gaskets can't be reused or at least should not be but the MLS gasket is supposed to sit for at least 30 minutes after all the torquing is done before you add fluids and run the car. I guess it's to allow the gasket to "set".

So as long as it's pretty much done all at once and the car hasn't been run.... You should be fine. I assumed time was of the essence when I saw your post and didn't think you would be hesitating to get the bolts in properly.

If you had put it off for a day before loosening and chasing etc, then I could see some serious problems. If it's done at the time the bolt skips, it should only be about 15-20 minutes before you are starting to cinch it back up.

Also of note, Honda doesn't specify that new bolts are required every time so that is the other part I took into consideration. The bolts can be reused unlike some motors of yesteryear.

EsotericImage

iTrader: (8)

If the HG hasnt been heat cycled, then its fine to re-use

umhb_dad

bummer! it blew out after 3 hrs of run time. Took the head back off with the manifolds and re-checked for flatness - all good.
Also used easy-off oven cleaner to clean the block better - the first gasket remover stuff was some permatex 'non-toxic' (a.k.a "does not work") junk.
This time i chased the threads, used graphite lubricant on the bolts, and a FelPro MLS perma-torque gasket (first gasket was from e-bay by 'mizumo auto' - bad mistake). Would have gone with an OEM but the dealership was closed
Torqued up great. Funny though that after about an hour of putting it all back together i re-checked the torque and just one of the bolts went down a bit more, maybe an 1/8 of a turn. These were new bolts too.
Holding well after several several hours and hot/cold cycles

EsotericImage

iTrader: (8)

FelPro is known for small leakage for HG's only.. But thats for Bseries. SO IDK on a D.

Good luck and make sure you bleed it correctly then keep an eye on the temp