Exhaust Gases in Coolant, Now What?

[mattnw]

Hi All,

I've done a lot of searching and haven't found a distinct answer to my questions. I have a 1986 Van.

Situation:
My engine temp fluctuates, though it hasn't gone much past the halfway point on the gauge. Every time I drive the van, then check the coolant level, the coolant in the filler neck is almost not visible, and the level in the overflow tank is slightly less. I refill both to full, drive it again, same thing happens. No white smoke coming out of exhaust. No pressure leaks from a coolant pressure test. No visible leaks. No coolant in oil. BUT when my coolant was tested, exhaust gases were found in it.

Questions:
- Is there anything that this could be other than a leaky HG?
- Do I have to full-on replace the head gasket now, or is there another way to fix this being it seems to be a small leak?
- Is something like Bar;s Leak an option, or is it not advisable to use any sort of stop-leak product?
- Would it be better to replace the head gasket or just replace the engine?
- Are there any head gasket replacement guides on here? Too much comes up when I use the search function, and I haven't been able to find any.

I really appreciate any help. Last optional question is does anyone know of any shops in Portland/Vancouver, WA area that is willing to work on these vans? Backyard or brick and mortar?

Thank you for your time! I hope to contribute more to these threads as I learn more about the van.

[Burntboot]

The threads you need are located in "articles" under "Tim's tech tips".
Gwen posted a very useful article on how to search as well, its very handy if you use it.
Given that it isnt over heating, it might be wise to run down all the other issues first.

Do you have any idea how old the coolant is?
What work has been done in the past?
What maintenance have you done since purchasing?
Is it a factory stat? how's the clutch fan?Hows the rad, hoses......?

If the engine is low on coolant and the expansion tank is not empty, thats a problem, theres a thread on that
Temp should run about middle of the gauge (assuming the dash gauge is accurate) and should be steady

How did you resolve your previous issue, perhaps you could post an update on the other thread, someone searching in the future may benefit from your experience.

Bar's leak is best avoided

[mattnw]

Thanks for the reply, Burntboot. I followed up on that other post.

I found the article "Other parts to replace while replacing Head Gasket" by Tim, and think that that'll help me greatly if I go the route of replacing the HG myself.

Coolant is newer. Nothing relating to the coolant system has been done recently, to my knowledge. I only bought the van a few months ago.
Since purchasing I've replaced the valve cover gasket and oil pan gasket. And had the distributor reinstalled by a mechanic. I also replaced the radiator cap and the filler neck, as well as all sensors that plug into the filler neck. I also replaced the coolant temp sensor that screws into the block. I will plan on replacing the fan clutch and t-stat soon, though (1) my fan does get faster at higher temps, and (2) I don't think that these parts could cause exhaust gas to be found in the coolant.

I'm just assuming that being exhaust gas was found in the coolant, and there are no (a) visible leaks, or (b) leaks that arise during a coolant system pressure test, the problem must be a head gasket leaking into the cylinder.

Do you have any advice on the route I should take? I'm seeing my options as:
(1) Replace head gasket myself. I'm somewhat mechanically inclined, but I'd have to buy a fair amount of tools, and it would take me a ton of time. Upside is that I could probably replace some more parts while in there, and save some money.
(2) Pay a mechanic to replace head gasket. This would cost more money, and I'm having trouble finding a mechanic in the Portland area that will even work on this car.
(3) Pay a mechanic for a full engine overhaul. Would cost more, but hopefully also offer more security in the future. Don't know if I can afford this.
(4) Pay a mechanic to replace engine. Not sure what this entails.

Any advice is much appreciated. This isn't a daily driver for me, but rather a van we wanted to use for some road trips in the future, i.e. reliability is a must. Any help from you all who are much more experienced with these vans would be so helpful. Thank you.

[Burntboot]

I would start with changing the coolant.

It's probably a waste of money and time, but what if the PO filled the system with used antifreeze that came from his truck with a blown motor?
I know it sounds stupid, but I have been burned by things like that before.

As to the repairs, I am a devout DIYer.
I have never had a good experience subbing out car repairs, though I have tried many times.

Repair shops have this awful constraint where they need to earn a profit (so they tend to work as fast as they can)
Working on vans is rarely profitable, not because they are difficult, but because they are unfamiliar.
The extra thinking/pondering/contorting time makes the job less profitable.
Would you bust your hump to earn $100 when you could make more money, in less time, doing easier work?

If you're doing it yourself, you are less likely to cut corners and more likely to action other bits, while you're in there.

As long as the rest of the engine seems decent I would replace the HG, finding solid used motors is starting to get difficult.
We haven't been able to source (pre '90's) JDM engines up here for years, suppliers are only carrying "current" engines, <20 yrs old for the most part.