Coolant leak

[Maddog]

Hello all, I’ve been lurking around the forum for a while reading and researching Astro vans. About a year ago my wife and I bought one in Phoenix, AZ. It’s a 1998 cargo van. Has windows all the way around which is nice in Tucson city traffic.

After driving it for several months I would occasionally notice the smell of antifreeze. I would look but never see a leak. Started monitoring the coolant level more often and it would consistently drop low, I would top it up, repeat cycle.

Then last month on my way to Wally-world it started overheating real fast. So I pulled into a parking lot (quadrillion of them in Tucson) and shut her down. Temp gauge had hit red in that short span of time. Not much steam coming from under hood, so I carefully popped the hood.

The top radiator hose had blown off. I put it back on and retightened the clamp. Sat there for a bit in 110°F weather. Then filled reservoir with water, fired it up and drove few miles home. Got home before it hit the red again.

No white smoke, nor smell of coolant from exhaust. Drained oil and sent it in for analysis at Blackstone-labs.com, results: no trace of coolant in oil.

Drained overly water diluted coolant. Installed new thermostat and radiator cap. Topped up with coolant mixture. Drove it a few short trips after letting it idle for 30 minutes. Still no smell nor smoke from exhaust. But checked coolant level and it’s low again. Ok, let’s check another way.

Bought Stant radiator pressure tester. Pressurized system, yup I could see the coolant dripping down from engine. Pulled doghouse and could see it leaking out from underneath intake manifold. There was a strange gooey substance at the gasket juncture. I also noticed some weird sludge in coolant reservoir.

Now I’m thinking that the previous owner had a gasket leak and threw some sort of stop-leak in it just to sell the vehicle.

It was weird too because when we first bought the van the paint was really clean, no oxidation. Sure some small dents, but that is normal here in the land of “I don’t care what you drive, your vehicle is my door stop when I kick my door open. Welcome to southwestern hospitality!”

But within six months all the paint started flaking off, lol. I think the previous owner painted it with Rustoleum. I had told him I needed a vehicle to haul my wife’s wheelchair in and she’s on disability and I am her full time caregiver.

When we were looking at buying the van I asked the owner about any issues with the van and he said “there’s nothing wrong with it”. Mileage is pretty low at 110,000 miles. Looked under hood, super clean (he detailed it) and oils were nice and clean no burned smell, etc.

Right after we bought it I took it in for emissions at MVD and it wouldn’t pass. They wouldn’t even test it because the OBD II port under the dash was loose. I drove home and took a look. The mounting surface had been broken and the previous owner had pulled the port up under the dash and zip-tied it up out of sight. How he broke the bracket I haven’t a clue. Hissy-fit kicking feet while stuck in traffic?

I pulled it down, drilled some holes and remounted it. Drove back to MVD and it passed emissions test. So, man knows I’m not in the best financial position and have a very ill wife so he sells me a doctored up vehicle that he knows won’t pass emissions and will have cooling issues down the road and has been detailed to sell to some unsuspecting person.

Guess he has no conscience.

Anyway, sorry for the long story. Now I’m about to purchase the Fel-pro gasket kit to fix it right. I am debating whether to do the mpfi spider injector conversion while in the doghouse.

Several questions:

1. I do think I will sell the van as I would prefer to buy an AWD version. Wife and I are planning on moving back to snow country where land is cheap and living much simpler, lol. So do you think it would be worth doing the spider conversion as a selling point?

2. Should I plan on doing the head gasket too while under the “hood” or is that not worth it, i.e. too much of a hassle?

3. Are head gaskets an issue with Astro vans?

As in when I replace the intake gaskets will leaking pressure now not leaking build up enough to blow out the old head gasket?
I don’t want to chase a weak link around and have to tear down again to do the head gasket in a week or two, lol.

I want to fix it right for my own conscience and whoever buys it and I might be driving it a bit until I sell it. I don’t like passing issues on to others. I have put some sound deadening material inside on roof and reflectix to reduce heat buildup. Also had windows tinted dark but legal. May fab up some wood paneling, etc inside for start on mini-camper. Paid $3,200 for it. Thinking with a bit of low cost materials and work I can resell it for around $6,000.

I appreciate any thoughts on any of this.

Toasted in Tucson, lol. From heat, not a-k-hall.

[AstroWill]

Welcome to the site!
The lower intake manifold gasket failure is super common, lots of posts around here. Head gaskets usually don't go unless it has really been overheated.

IMO, if there is any possibility of keeping it I would definitely do the spider while you are in there. If you are selling, it would be a selling point to someone that knows what it is, but for the average Joe, not so much.

[Leeann_93]

You will find, when you get your gasket set, that it comes with a tube of RTV. That is the 'gooey' substance at the back of the intake manifold - it was installed at the factory like that and it will be installed by you like that as well.

I hope you bought the Fel-Pro set that ends with -T. That's the plastic-coated metal gaskets that last longer than the OEM plastic gaskets.

LIM (lower intake manifold) gasket failure is standard on the 4.3. The original formulation of Dex-cool ate plastic, turning those gaskets to mush.

Head gaskets, I would only replace if they are bad. Valve cover gaskets, I would replace. The spider upgrade to MFI is worth it, imho.

[Maddog]

Thank you for the quick response!

I really like the van, it drives nice with great visibility. I like sitting up above traffic. Had a lot of lifted trucks, Jeeps over the years. If the van were AWD I would for sure keep it! But they’re harder to find now in good shape.

I grew up south of Rochester, NY out in the sticks, lol. Really miss that country, snow, skiing, wood stoves, gardening, etc. So want a good snow runner when we get back there. Better to buy out here...no rust buckets!

I haven’t bought the gasket set yet. Thought I would check in with those who have more knowledge than I on these vans.

Good to know about the Fel-Pro set that ends in a T. I appreciate that bit of info. I’ve worked a few times as a mechanic, rebuilt a few engines, r&r transmissions, clutch, all that jazz, etc. So not new to swinging a wrench. But it’s tough in the heat, lol.

Looking at building a tiny home/camper in a box truck of some sort and having an AWD or 4x4 to tow behind. Once set up it’s moving time. If I was staying here I would probably just keep the van, but that isn’t an option now that my wife and I decided what/where we really want to live.

Going to clean it up under the doghouse, it’s pretty grungy on the engine. I checked the price on the spider and it’s not too bad. Since we might be driving it for six months or so before we sell it I think I will go ahead and do the spider conversion. At least the plug wires look fairly new/non-stock. The owner said it was a company truck (I’m guessing his company) and it was routinely pm’d. Who knows, lol.

Thanks again for the help!

[Leeann_93]

Sitting up above traffic and in really comfortable seats is nothing to sneeze at. I grew up 5 miles from the MA border in CT; my brother went to Ithaca College and my mom to Cornell; my brother now lives just outside Buffalo. AWD is awesome. AWD with the G80 is even more awesome (I have a '93 Bravada with 4.3, AWD, 3.73 with G80). I'm told that even RWD with the G80 does really well in snow.

The good Fel-Pro LIM set is MS98002T.

[Mmusicman]

The top radiator hose had blown off. I put it back on and retightened the clamp. Sat there for a bit in 110°F weather. Then filled reservoir with water, fired it up and drove few miles home. Got home before it hit the red again.

Blowing the hose means you INSTANTLY blew most of the coolant out of the engine and system.
This of course is very bad.. and would cause extreme overheating almost instantly.
No coolant in engine creates severe hot spots and makes it even worse.
The temp gauge typically won't read accurately without coolant either (meaning it's worse than it appears).

Filling the "reservoir only" after blowing system out will not adequately refill the system.
If there is any pressure in the system (steam etc).. then it won't pull water from the reservoir at all.
You need to actually fill the radiator. This MUST also be done slowly and carefully (after it cooled enough to open cap). With engine running, you slowly add water to radiator until full. Cold water too fast in an overheated engine can be catastrophic, so it must be done slowly with engine on, circulating coolant/water as it is added . If you only filled reservoir and it didn't fill the radiator, you likely ran it extremely hot even more... as you stated.

The 4.3 does NOT like being overheated.
Typically you will blow gaskets, and possibly head gaskets.

Head gaskets are a LOT of work.
I'd be certain they're bad before I changed them.

I would not change the spider unless it's bad.
It won't likely be much of a selling point.
But the best time to change it (if you decide to) would be while doing the heads, if they need it.

Good luck

[Maddog]

I’ve a good friend that lives in Buffalo. I used to go to see the Buffalo Bills play years ago, lol. Lot of awesome country up there in the northeast.

So I put the gasket set you mentioned in my amazon cart and a set of new intake manifold bolts.

Near as I can tell, this is the spider injector set I need for a1998 Astro van: ACDelco 217-3028 GM Original Equipment Fuel Injector Kit with Bracket.

Mmusicman, thank you for jumping in. I appreciate it. When it all cooled down the next day and I drained what was in the system I replaced the thermostat and refilled with proper coolant. Put a new cap on it. When I let it idle for 30 minutes and then drove around for another 30 minutes it seems ok, it didn’t sound out of the ordinary. No knocking, squealing, Pinging or other strange noises. Other than the leak I found the next day by pressure testing the system it seems ok, but I’m not 100% sure, lol.

Do you think it will probably be ok after the LIM gasket change?

I figured after it’s all done, next oil change (at 3,000 miles) I will do another oil analysis. I think I will do an exhaust leak test on the radiator too before I tear into it.

[sixsix]

Welcome to the Forum - very detailed 1st 2 posts are so underrated.
There are "detailed files" available to help w/ confidence & you've noticed...

We're just an answer away.

[Maddog]

On the other hand, maybe the damage will take a bit to present itself?

Hope this overheating doesn’t open a can of worms for me!

[Mmusicman]

You might try doing a compression test (as well as leak down tests)

[Maddog]

Thank you, I’d rather try to diagnose it as much as I can before I tear into it too much so I can order all the parts in one shot. I hate working on vehicles and getting halfway through the job and then have to wait several days to a week or more for new parts. Rather do it all in one shot over a few days if possible, lol.

[Maddog]

Well I tore into the engine today. When I pulled the plastic plenum and spider injectors out they were covered in a black carbony substance that was oily feeling and smelled of gas. I’m wondering if one of the injectors is leaking under there?

I couldn’t believe how grimy it is under that plenum cover, every spider leg covered with that wet sooty stuff. I’m guessing that's not normal. Pulling the IM off tomorrow and see what else looks gunked up.

[Maddog]

Also was going to drain the coolant from the block but the drain plug is in there so tight I decided not to risk stripping it out. So just have to deal with coolant making somewhat of a mess when I pull the IM. Drained what I could from the radiator.

[Leeann_93]

With CSFI, that is normal. It’s not normal with MFI.

[Maddog]

Thank you for the reply I didn’t know that. That’s just crazy, it’s like designing an ac system for a vehicle that sucks air in from right behind the tires where all the road debris gets kicked up and then piping it into the cabin with no air filter.

“You want fresh air? Here, breathe this!”

Of course I can always blame my older brother as he’s a design engineer, lol. I’ll have to ask him if he worked on the initial design of that CSFI. LOL!

Switching to the injector upgrade. My spidey-sense is tickling me to do the switch. I might be driving this vehicle for a year or so before I sell it and I want it running good.

[Maddog]

Also I’d really like to flush the Dex-cool out of the system and go to the green kool-aid but I can’t flush the system properly where I live. Landlord wouldn’t be too happy, lol. But from what I understand the orange tang has been reformulated so maybe it won’t gunk up in the cooling system so much.

[Sailing_Faith]

I can’t stress enough the need to be fastidiously clean when changing the gasket... don’t let any of the old gasket or the scrapings fall into the valley... it is not uncommon to have a bearing go after a gasket replacement when a bit of debris falls into the motor.... And of course do an oil change immediately after you are done.
otherwise, it is pretty straight forward.

[Maddog]

Thank you for the heads up on that. I will be sure to be very careful with cleaning things up.

Before I pulled the plastic plenum I started scraping and brushing off some of the gunk and vacuuming it up. Once I pull the IM I will plug all the ports before cleaning off old gasket. I will keep my shop-vac handy and suck up debris as I go.

Here’s a little tip that might help newbies somewhat apprehensive about engine work:

If you are worried about how to put things back together and in what order, it’s a given you should be taking pictures. But one thing I like to do is label a ziplock bag with the name of the component and then put the bolt/nuts and smaller component or bracket in that bag. Now a lot of people may do this but here’s where I go a step further.

I place each labeled ziplock in a box in the order in which I took them off, stacking them in a horizontal row. Then when you reinstall the parts simply start with the last bag you put into the box and work your way to the front of the box. Each bags tag you wrote on it tells you which part to grab to go with that bag of bolts. You can also draw a simple picture on the front/back of baggie to denote where a longer/shorter bolt might go compared to the others in that bag. This is a real confidence booster for those with poor memory too. Of course you want a longer sort of narrow box, like a shoebox. You might need two boxes if they are small. If the box is too wide the baggies may slip around and get out of order. So...

If you’re worried about messing the order of the baggies up:

You can sequentially number the bags. Then when you reinstall parts simply grab the highest numbered baggie and work your way back to number one.

Simple easy way to not have to stress about “What part comes next?” during reassembly or “Which bolts go with this part?” especially if you have to wait several days or weeks before you can reassemble.

This gives confidence during tear down since you’re not worrying about having to recall exact order to put things back and what bracket, component, part and bolt/nut goes together. And a big plus is you don’t mislay or lose parts!

I know some guys throw everything in a box or heap on the floor, lol. Usually these are guys who have done the same job enough times to know what goes where. But even then, if they organize parts and bolts/nuts as they remove them even they would notice much improvement in speed of reassembly. I’ve seen these same guys fumble around looking for a small part or bolt, etc. that either got misplaced in the jumbled mess or accidentally kicked under a bench. Idiotic, lol.

So far the job has not been anywhere near as difficult as I imagined working in the doghouse would be.

[Maddog]

Just been taking my time working on my van. Temperatures are not coming down much at all here in Tucson.

Anyway, pulled the intake manifold off and cleaned the block real good, then taped it off and then pulled valve covers. Time to start cleaning parts, lol.

How do I post a picture here?

[dcsleeper]

top right
your photo albums
new image
then create your post
in the full editor, click gallery on the right end of buttons
click insert image into post under pic you want.

or something like that...