Doug_B_928

The first couple of times I moved my car this spring I noticed a couple of orange (dexcool coolant) drops on the floor under the engine area of the car. I figured my coolant tank/hose may have a leak/loose fitting.

Since last running the car I haven't seen any drops on the ground. The only difference is that the last time I started it I just moved it around and didn't get it up to temperature.

Today I had a chance to look underneath and I saw where the coolant leaks appear to be coming from.....ugggghhhhh. The pic below shows in a red circle where I think the leak is from on the left side. You can see where the coolant has been dripping down. Is this a head gasket leak? The pic with the blue circle is from the right side and shows where coolant has been running down. I looked from underneath with a mirror and looks like the source of this leak may be the plug on the back of the head. I've done some searching and am scared by what I read. Based on the pictures, are these classic signs of an engine that is rotted on the inside from acidic coolant (I've read of this, but am wondering if such engines have worse leaking than this)?

I don't see any visible signs of oil in the coolant reservoir, and the oil on the dipstick looks clean (was just changed last fall before winter storage). The car runs the same as always.

What should be my next steps (I've never removed an engine)?

Mrmerlin

Hi Doug please add your model year and options /trans to your signature,

At the top click user CP then edit signature. Than
On to your issue the HGs dont usually leak,
and if they do its more of a weep along inside edge of the HG in the Valley of the engine,
this can be confirmed by inspecting the HG edge,
if you see white crusty deposits then its a weeper


SO more than likely the leak is from the block off plate at rear of the head and a new gasket and new bolts should be fitted.

drain the radiator (about 1 gallon is necessary) then remove the fuel damper,
and or just remove the damper bracket.... well depending on the year of your car.

NOTE do this outside if possible as fuel may leak to the ground, if the damper line is opened
then remove the block off plate there will be about 8 oz of coolant lost.

Check the opposite head for a leaking plate, where the HCV short hose connects
NOTE if the heater control valve is older than 5 years replace it,
along with the short hose ,
get a new coolant bottle cap as well

Doug_B_928

Thanks, Stan! It's a 79 5 speed. Have I correctly identified the parts of which you speak (see pic below)? The pic is of the right side and it does appear to be leaking from there. Similar on the other side. There is also wetness in the valley on both sides. It looks like oil but could also be coolant mixed with dust/dirt. Where is the fuel damper?

Mrmerlin

Doug thanks for adding your car info it makes for a better diagnosis.

well since you have a 79 you dont have a fuel damper ,
I was guessing due to lack of information on the year of your car.

In this picture it appears to have a leaking fitting ,
follow instructions above to RnR both plates ,
one on either head,

I would swap out the HCV and short hose,
toss the old parts into the tool tray for spares, since you will be disconnecting these parts

NOTE you might consider using some Hondabond 4 on the new gaskets this should prevent future leaks

Doug_B_928

Thanks, Stan. Had you not put me on the track of these plates I may not have slept at all last night. I will do as you say. A couple of additional questions:
1. I follow the WSM on changing the coolant. IIRC, it doesn't say to flush out the old one with water or any kind of solution. Should I be doing this?
2. Having read those other threads, I'm still a bit concerned about the interior of the engine becoming Swiss cheese. Is there a safe and easy way to check on what old coolant may have done to the engine? Maybe an inspection camera somewhere?

Doug_B_928

Oh, forgot my third question:
3. I don't know that we can get Hondabond up here (I've only read about it on this forum). Is there a suitable substitute; e.g., the silicone RTV gasket sealant I used for my WP?

Ed Scherer

Doug, I got Yamabond 4 (equivalent to Hondabond 4, I think) at a local motorcycle shop without even having to look around much. Seems to be very common, and the guy at the shop mentioned that they sell a lot to people for non-motorcycle use (I guess word gets around!)

Doug_B_928

Good tip, thanks Ed.

Mrmerlin

a motorcycle shop should have have some kind of semi permeable sealant like Hondabond 4 or Yahmabond 4

If your going to replace the coolant now is also the time to replace the thermostat and O ring and rear seal if you have one,
use new bolts with anti seize on them for the water outlet and Dow Corning 111 on the O ring.

To flush the coolant it requires removing the block drains,
you will get about 2.3 gallons from the engine,
once the block is drained.
install the plugs.

Then remove the rear HCV from the engine and the 1 inch transfer hose from the water bridge.
flush water into the HCV inlet and let it drain from the 1 inch hose,
add some water to the coolant bottle.

This will flush the heater core and coolant bottle and transfer lines,
then connect them back and refill.

I wouldnt flush the block, once its drained its ready for fresh coolant

Refill the system with 2 gallons of coolant and 2 gallons of distilled water.
To fill the system ,
connect all of the hoses and slowly fill the coolant bottle,
this will take a few minutes as the air will be bleeding out of the water bridge and the radiator,
on the last gallon mix the the half full bottle of coolant with 1/2 gallon of DI water,
so you have a 50/50 mix,
whatever wont go in can be used for topping up in the future.

To do this job you need

2 gaskets, one for the HCV outlet and one for the block off plate, NOTE they are both different.
Heater control valve.
Short hose.
Thermostat.
O ring.
Rear thermostat seal, if you have one?
2 new bolts for water outlet. use anti seize on the bolts , ACE hardware has them
New coolant bottle cap.
2 gallons of G O5 coolant.
2 gallons of Distilled water found at the supermarket.
1 tube of Hondabond 4 or Yahmabond .
1 tube of Dow Corning 111. Found at Amazon.com

NOTE the DC 111 has many uses for every rubber bit on the car,
especially the window lower seals on the door it will keep them soft dont let it get on the window.

This should cover your coolant system refresh

NOTE inspect all of the hoses that connect to the water bridge ,
each outlet has a nub on the top of it and this nub can wear through the inside of the hose,
look carefully into the hose and see if it has been damaged,
if you see a hole then replace the hose,
NOTE the top rad hose has a large snap ring instead of a nub so look for damage.

NOTE there isnt really any way to inspect the interior of the block for damage other than removing the heads,
most corrosion damage will occur on the head surfaces adjacent to the sealing rings of cylinder bores,
you can also look along the inside of the V where the heads meet the block and look for crusty white deposits along the HG edge ,
if you see this then the HGs are weeping, and not a deal breaker its letting you know that HG replacement is in your future

Doug_B_928

Thanks, Stan. My list for Roger keeps getting bigger . I will order parts and report back (likely with clarifications). Is there any way of assessing potential damage from old coolant without tearing into the engine? Or, if it's running fine there's no damage?

Doug_B_928

Oh, is the orange dexcool the same as Z05 coolant?

Kiln_Red

No, they are different formulas. If it were my car, then I would convert to G05 or a similar quality phosphate free coolant.

Your cooling system will be grateful if you follow Stan's recommendations and switch to G05.

Doug_B_928

Okay, I sourced the G05. I'll drain the whole thing, follow Stan's flush instructions, and then replace with G05. Need to wait for the parts; still waiting to hear from Roger.

Doug_B_928

When you say to flush with water, do you use distilled water for flushing too? And, how much should I run through in the manner described above?

Mrmerlin

I would suggest to flush the heater core and coolant bottle with DI water ,

you dont want to flush the block, JUST drain it and refill it with the fresh coolant and DI water
reason being that this flushing could wash away the loose particles of HG and cause them to fail.

It would take about 1 gallon to flush the heater core